Key Takeaways Quantum photonics, a cutting-edge field, leverages the quantum properties of light to revolutionize information processing and communication.  By manipulating individual photons and their quantum states, this technology enables groundbreaking applications.  Quantum computing promises to solve complex problems exponentially faster than classical computers.  Quantum communications ensure secure data transmission through quantum cryptography.  Additionally, quantum photonics finds applications in quantum sensing and metrology, offering unprecedented precision. Quantum photonics is the technology of optics on a quantum level. With applications ranging from quantum information processing to quantum computing and quantum communications, this emerging field has the potential to transform how we work with information.  On a practical level, quantum photonics involves generating, manipulating, and detecting light in ways that enable control over individual photons or pairs of photons and their quantum states. Quantum photonics is the power of light harnessed in new and exciting ways. What is Quantum Photonics? But what does that mean, in practice? Light has both particle-like and wave-like properties, and when you’re working on the quantum level both of these properties are very important. The building blocks of light, so to speak, are photons. They have no mass and move with the speed of light, but they do have energy. One way of thinking of photons is as a quantum counter: a counter of the excitation of an electromagnetic field. A photon is characterized by its energy, and this energy never changes from the time a photon is created till it is destroyed. Its wavelength, however, may change as the index of refraction of the substance it is traveling through changes. While a beamsplitter can’t split a photon, it can reshape its wavefunction, and it can also cause quantum interference effects between photons. Silicon photonics and a variety of different optical devices are used in quantum photonics.  When working in quantum photonics you might be using single photon sources, special devices that can produce individual photons on demand, or photon pair sources that produce a pair of entangled photons. Entangled photons are photon pairs with linked quantum states and are essential to some applications.  To measure quantum states and, in quantum cryptography, quantum key distribution, you may need to use a photon counting detector that is capable of registering the presence single photons.  Optical resonators can be used both to store photons and to control and manipulate their quantum states.  Another way to manipulate single photons involves using what are called quantum dots; tiny semiconductor particles that absorb and emit photons. Electric-optic modulators also provide reconfiguration options.  Another important component of the quantum photonics toolbox  is the photonics integrated circuit. The analogy of an ordinary integrated circuit, this is a combination of laser diodes, waveguides, filters and gain media. To learn more about integrated quantum photonic circuits, have a look here.  Quantum photonics circuits may consist of many tiny optical components embedded on a tiny chip. Applications of Quantum Photonics Quantum photonics is an emerging field that can be used to make computing, communication, and information processing faster, more reliable and more effective. Although some applications of quantum photonics are in use today, we’ve only just begun to tap the potential available to us. Here we’ll look briefly at the potential of quantum technologies, for today and for the future. Quantum Computing Quantum computing involves using photons to process information, and even to store it in quantum memory. The basic union of information is the qubit, the analogy of the bit in classical computing. Essentially, this is a photon in one of two polarization states. The wave properties of photons mean that a qubit may exist not only in one of its two states, like a  traditional bit, but also in superpositions of these two states.  Linear optics may involve using directional couplers and phase shifters to give a qubit spatial degrees of freedom.  One example of a quantum computing chip is Google’s Willow chip. It includes just 105 physical qubits of computing power, but, according to Google, can solve a problem in five minutes that— theoretically—-would take the world’s fastest supercomputer a full ten septillion years.  Although it has yet to be put to many practical uses, the potential is enormous. Quantum simulation is one way to explore this potential with ordinary computing devices. To learn more on this topic, look up our article on  optics for optical quantum computing.  Although quantum photonic chips have yet to make their way into the mainstream, they have the potential for extremely quick, efficient computing. Quantum Communications Quantum communications is based on the same qubits we see at work in quantum computing, and provides a quick and secure way to send sensitive data over long distances.  Quantum cryptology is a special subfield of quantum communications, and one important application of it is quantum key distribution. In quantum key distribution, qubits are used to send random number sequences from an integrated single photon source to photon detector, either through free space or optical fibers. The photons may be encoded via polarization, via phase, or via entangled photons.  Quantum Photonics at Avantier Avantier is a pioneering producer of optics for quantum photonics, and our experienced team is available to make your custom order a success. Contact us today to set up an initial consult or put in your custom order.  References Giles, Martin. Explainer: What is quantum communication? MIT Technology Review (2019), https://www.technologyreview.com/2019/02/14/103409/what-is-quantum-communications/ Han-Sen Zhong et al., Quantum computational advantage using photons. Science 370,1460-1463(2020). https://www.science.org/doi/10.1126/science.abe8770 Luo, W., Cao, L., Shi, Y. et al. Recent progress in quantum photonic chips for quantum communication and internet. Light Sci Appl 12, 175 (2023). https://www.nature.com/articles/s41377-023-01173-8 Pearsall, Thomas P. “Quantum photonics.” Springer Nature,  (2019). https://link.springer.com/book/10.1007/978-3-030-47325-9 Wikipedia, Integrated Quantum Photonics, https://en.m.wikipedia.org/wiki/Integrated_quantum_photonics Related Content

Key Takeaways: Adaptive optics enhance optical system performance by correcting wavefront distortions in real time using deformable mirrors, wavefront detectors, and controllers.  Initially developed for astronomical telescopes to mitigate atmospheric turbulence, it now also improves imaging in biological microscopes and retinal diagnostics.  This technology enables precise corrections, enhancing resolution in complex environments, such as thicker biological samples and dynamic ocular structures.  By actively adapting to aberrations, adaptive optics significantly advances optical applications in science and medicine. Introduction to Adaptive Optics Adaptive optics is a technology designed to improve the resolution of optical systems that may be affected by environmental factors or the state of the observed object. In real-world applications, optical systems often deviate from ideal performance, necessitating correction measures to enhance imaging quality.  A familiar example is the human eye. When vision is impaired due to nearsightedness or farsightedness, corrective lenses, such as glasses, address these aberrations. However, traditional corrective lenses are not adaptable. If a person’s vision deteriorates further, a new pair of glasses is needed. This highlights the need for a deformable correction mechanism that can adjust dynamically to the actual conditions of the imaging system. In adaptive optics, a deformable mirror is incorporated into the optical system. This mirror measures wave aberration in real time to correct distortions, reducing environmental impacts and improving imaging quality. Essentially, adaptive optics actively corrects errors in optical systems, combining scientific principles with engineering applications to play a crucial role in modern optics.  Understanding Wavefront A wavefront refers to the surface formed by points that are in the same phase during light wave propagation. A point source generates a spherical wavefront, while a parallel source generates a plane wavefront. Ideally, the wavefront should be perfectly spherical or planar. However, due to aberrations in optical systems, even a perfect wavefront can deviate and exhibit wavefront error after passing through the system. Wavefront error Device of Adaptive optics Adaptive optics operates through a closed loop of detection, control, and correction, utilizing components such as wavefront sensing detectors, controllers, and correction elements.  Wavefront Sensor: Before adjustments can be made, the wavefront situation must be assessed. A wavefront sensor is a specialized component that measures wavefront distortion in real time, serving as the core component of an adaptive optics device. There are various types of wavefront sensors, each with distinct operation principles. A  common wavefront sensor, for example Hartmann-Shack sensor, consists of a microlens array and an image sensor. The wavefront is divided into small regions by the microlens array, which projects images onto the sensor. If the wavefront is tilted, the image spots shift from their ideal positions. Each microlens acts as a microelement, allowing for the calculation of the average slope of the wavefront in each region. This data is compiled to reconstruct the complete wavefront profile. Hartmann-Shack Wavefront Sensor Wavefront Controller: The wavefront sensor provides the measured wavefront shape information to the wavefront controller. The controller processes the sensor data and determines a compensation strategy using algorithms. Correction Element: After calculating the compensation scheme, the wavefront controller sends signals to the correction element, which compensates for the wavefront errors. Simply put, the correction element generates a reverse wavefront aberration to counter the original aberration, effectively canceling the aberration out. The correction element is deformable; by applying voltage or other means, its surface shape can be altered. This adjustment modifies the optical path difference, producing the required correction. Applications of Adaptive Optics One of the first applications of adaptive optics was in astronomical telescopes. The resolution of these space telescopes often cannot achieve the ideal diffraction limit due to irregular movements in the Earth’s upper atmosphere. Atmospheric turbulence creates wave aberrations that significantly hinder the telescopes’ imaging capabilities of celestial objects.  Wavefront sensors measure these wavefront distortions caused by atmospheric turbulence, while deformable mirrors make real-time corrections to improve image quality. Consequently, adaptive optics has become an essential technology in modern astronomical observation, with nearly all large telescopes now incorporating adaptive optics systems. High Resolution Biological Microscopes Biological microscopes are precision optical instruments used to observe transparent or translucent objects, such as biological slices and living tissues. For example, when imaging a biological sample with an infinity-corrected microscopy objective lens, the light emitted by the sample forms a spherical wave. This light wave is collected by the objective lens, converted into a plane wave, and then focused by the tube lens before being captured by the sensor. However, the complex internal structure of biological samples, particularly in thicker specimens, often leads to optical aberrations. Combined with optical system errors, these aberrations significantly affect imaging quality. To achieve high resolution imaging, correcting these errors is essential. Adaptive optics techniques have been introduced into various microscopy imaging systems to correct aberrations and enhance image resolution. A beamsplitter and a deformable mirror are integrated into the optical path. The beamsplitter separates a light beam for wavefront analysis, and this information is fed back to the deformable mirror to make necessary corrections. Adaptive optics can also predict and correct wave aberrations using adaptive correction elements based on wavefront detection. Biological Microscope Retinal Imaging Another significant application of adaptive optics is retinal imaging. Ophthalmoscopes are used to examine the retina for fundus lesions. While traditional ophthalmoscopes can detect and diagnose retinal issues, they struggle to observe fine retinal structures due to limited resolution and inherent eye aberrations. Although compensating lenses can reduce primary aberrations, their effectiveness is limited. Adaptive optics technology allows for real-time correction of dynamic eye aberrations, overcoming the limitations of traditional ophthalmoscopes and enabling high-resolution retinal imaging. Retinal Imaging Comprehensive understanding of Adaptive Optics In conclusion, adaptive optics represents a transformative leap in optical technology, addressing and correcting aberrations in real time to enhance imaging quality across diverse applications. From revolutionizing astronomical observations by compensating for atmospheric turbulence to enabling high-resolution biological microscopy and retinal imaging, adaptive optics bridges the gap between theoretical precision and practical performance. Its ability to dynamically adjust optical systems ensures superior resolution and clarity, making it indispensable in both

Key Takeaways Ritchey Chrétien telescopes (RC telescopes) eliminate spherical aberration, coma, and astigmatism, ensuring sharp, distortion-free imaging. Their wide, flat field of view makes them ideal for galaxy mapping, supernova detection, and dark matter studies. Compact, lightweight designs reduce launch costs, while thermal stability ensures reliable performance in extreme conditions. RC systems support advanced instruments for multi-purpose missions. Iconic examples like Hubble and JWST showcase their impact.   The importance of RC telescope in Space Optics In the realm of space exploration, precision is everything. The Ritchey-Chrétien (RC) telescope has become a cornerstone for astronomical instruments, offering exceptional performance through its advanced optical design. Here’s why the RC telescope is pivotal in space optics and what sets it apart. Astrophotography and space-based observations demand unparalleled clarity. The RC telescope excels in eliminating optical aberrations: 1. Aberration Correction Spherical Aberration: RC telescopes are designed to eliminate spherical aberration through the use of hyperbolic primary mirrors and secondary mirrors. This ensures that light from celestial objects converges at a single focal point, enhancing image sharpness. Coma Correction: Unlike simpler telescope designs, such as Newtonian or Cassegrain telescope systems, the RC configuration corrects for coma, which causes off-axis stars to appear distorted or elongated. This is crucial for capturing accurate and uniform data over a wide field of view. Astigmatism Reduction: RC telescopes are designed to minimize astigmatism, further improving the focus and clarity of images across the entire field. This image shows the Ritchey Chrétien telescope with two pieces of flat field lens Example of an F=8.3 Cassegrain telescope, where on-axis performance achieves the diffraction limit, but off-axis aberrations, especially coma, are visible 2. Wide Field of View RC telescopes provide a wide, flat field of view, a critical feature for missions requiring detailed surveys of vast regions of the sky. Applications include: Galaxy Mapping: Capturing high-resolution images of galaxies across the universe. Supernova Detection: Observing transient celestial events. Dark Matter Exploration: Studying cosmic structures influenced by dark matter. 3. Compact and Lightweight Design Space missions are constrained by size and weight due to launch vehicle limitations. The RC design offers a shorter optical tube length compared to other high-performance optical systems, reducing the telescope’s overall size and weight while maintaining high resolution and performance. 4. Thermal Stability in Space Environments Operating under extreme and variable temperatures, space-based telescopes require robust designs. The RC telescope remains thermally stable, minimizing alignment shifts and reducing reliance on complex active adjustment systems. This stability ensures reliable, long-term performance. 5. High Reflectivity and Efficiency RC telescopes use advanced reflective coatings, such as aluminum or enhanced silver, to maximize light collection. This efficiency is crucial for studying: Exoplanets: Observing faint planetary systems around distant stars. Distant Galaxies: Investigating the universe’s most remote structures. Cosmic Background Radiation: Analyzing the remnants of the Big Bang. 6. Seamless Instrument Integration Flexibility is key for multi-purpose missions. The RC telescope’s design allows for easy attachment of advanced instruments such as spectrographs, cameras, and coronagraphs, enabling a wide range of observational techniques. 7. Space Applications RC telescopes play an indispensable role in various astronomical missions: Deep Space Exploration: Imaging distant galaxies and nebulae with unmatched resolution. Exoplanet Research: Supporting precise measurements for photometry and spectroscopy. Astrophysical Phenomena: Studying black holes, gravitational waves, and cosmic microwave background radiation. Deep Space Exploration 8. Iconic Examples of RC Telescopes Hubble Space Telescope: An RC design that has provided some of the most iconic images of the universe with minimal optical distortions. James Webb Space Telescope (JWST): Employing principles of the RC system with deployable optics, it observes infrared wavelengths, pushing the boundaries of what’s possible in space observation. A Telescope Designed for Space’s Challenges The Ritchey Chrétien telescope’s ability to deliver aberration-free, high resolution imaging in a compact and thermally stable form makes it essential for space missions. Whether mapping the cosmos, detecting exoplanets, or exploring astrophysical phenomena, the RC telescope continues to be a driving force in advancing our understanding of the universe. At Avantier, our exceptional engineering knowledge and decades of experience enable us to produce high precision optics, such as SiC mirrors and off-axis parabolic mirrors, for space optics. We provide customized solutions tailored to the unique demands of space-based applications. With top-notch techniques in designing and manufacturing optical lens assemblies, we are committed to supporting groundbreaking advancements in space exploration. Related Content

Key Takeaways Optics for UAVs must be lightweight, durable, and capable of performing in tough environmental conditions.  Key requirements include balancing size, weight, and power (SWaP), achieving high-resolution imagery from long distances, and enduring temperature and pressure changes.  Thermalized designs help compensate for material expansion, while ruggedized systems withstand vibrations, shocks, and flying particles. UAV optics are critical for various applications, such as vegetation analysis, search and rescue, and industrial inspections, utilizing multispectral, thermal, and machine vision systems for diverse imaging needs. Optics for UAVs must be lightweight and durable, yet offer superior performance even in adverse environmental conditions. These optical assemblies are in many ways the heart of any UAV system, and an unmanned aerial vehicle is only as robust as its machine vision system. Here we’ll look at some of the unique challenges that optics for UAVs must surmount— and the wide range of special imaging capabilities they can bring to an unmanned aerial vehicle. Requirements of Optics for UAVs When designing an optical system for a UAV, an optical designer will need to balance a number of important requirements. Size, weight, and power consumption— sometimes abbreviated as SWaP— are often thought as the big three. Especially when working with small UAVs, every gram directly decreases flight endurance. Weight and size considerations makes continuous zoom a good option, for instance, instead of packing a different lens for every field of view. But there’s more. Optical systems for drones and UAVs must be capable of capturing quality imagery, even from significant distances and under adverse environmental conditions.  Long focal lengths and a good field of view can aid imaging assemblies to produce high resolution images, and special coatings can reduce reflection under strong sunlight.  However UAV optics must also be ruggedized for mechanical shock, vibrations, extreme temperature differences, and pressure changes.  Here we’ll look at the ruggedization requirements for UAV optics. Temperature Changes The refractive index of many substrates depends on temperature, but that’s not the chief worry when it comes to temperature changes and UAV optics. The coefficient of thermal expansion (CTE) of each part must be carefully considered. Glass, metal, and other substrates expand and contract at different rates, and the size of a particular component will be different at different temperatures. Optics for UAVs must be built for the temperature changes they will encounter in the atmosphere. When different materials are used in an assembly, temperature changes can cause lenses to shift, become misaligned, or even crack. A system that will undergo temperature changes must be carefully designed to minimize these issues, compensating for changing sizes when heated or cooled. We call these designs athermalized designs.  Pressure Changes Pressure is another significant issue when it comes to optical systems meant to be used in drones and other aerial vehicles. An assembly designed to have inner and outer chambers at equilibrium when used at ground level will no longer be at equilibrium when outdoor pressure changes. Careful modeling at different pressure values enables optical engineers to design a system that functions well at the low pressures encountered at high altitudes as well as at high-pressure locations.  Mechanical Durability An optical system designed for use within a UAV doesn’t only need to be able to withstand pressure and temperature changes; it also has to be protected against flying particles and ruggedized to withstand vibrations, the shock of quick acceleration changes, and any collusions.  These factors are important to consider when choosing substrates, but it is also important to ensure the final design is as simple and robust as possible, with connections between components reinforced where appropriate.  Optics for UAVs should be designed with carefully sealed components to keep moisture and dust outside. Precise orbital detection of mid-sized debris can also be achieved using carefully designed orbital laser ranging and LIDAR techniques. Often passive optical means and solar illumination are used to first recognize a piece of space debris, which is then illuminated with an intense ns-pulsed TOF laser. The receiver telescope is equipped with single photon detectors, capable of detecting  backscattered photons. This detection method has been used to detect objects of as little as 10 cm in diameter, and typical ranging accuracy is about 3 m rms. Applications of Optics for UAVS The optics you choose for your UAV will depend primarily on your imaging applications and the purpose of the UAV operations. Measurement and control of height above the ground can be accomplished by either active or passive sensing, using machine vision systems that guide the vehicle autonomously at a desired altitude.  For vegetation analysis, high spectral resolution spectrometry, multispectral cameras, or NIR cameras can all provide different imaging capabilities. In search and rescue operations a mixture of RGB and thermal imaging—either short wavelength infrared (SWIR), medium wavelength MWIR, or long wavelength infrared are often used in concert to obtain fail-safe operations under poor environmental conditions. Industrial inspection also often relies on thermal imaging payloads. Optics for UAVs at Avantier At Avantier, we produce custom high-performance optics for UAVs, providing customers in a wide range of fields with the quality optical assemblies they need. Whether you are in industry, surveillance, agriculture or defense, we can work with you to design and produce the optics you need. Contact us today to set up an initial consultation.  References Johnston, C. (2012). Technical challenges for small UAV payloads. Electronic Military and Defense. https://smithmillermoore.com/Pdfs/technicalarticles/7-11_HT_EM&D_TechChallenges_forSmallUAV_Payloads.pdf Srinivasan, M. V., Thurrowgood, S., & Soccol, D. (2006, November). An optical system for guidance of terrain following in UAVs. In 2006 IEEE International conference on video and signal based surveillance (pp. 51-51). IEEE. https://ieeexplore.ieee.org/abstract/document/4020710/ Von Bueren, S. K., Burkart, A., Hueni, A., Rascher, U., Tuohy, M. P., & Yule, I. J. (2015). Deploying four optical UAV-based sensors over grassland: challenges and limitations. Biogeosciences, 12(1), 163-175. https://doi.org/10.5194/bg-12-163-2015 Related content

Key Takeaways VR optics utilize head-mounted displays (HMDs) to immerse users in virtual environments by projecting virtual scenes through an optical system, reducing eye strain.  Key performance indicators include field of view (FOV) for immersion, EyeBox for comfortable eye movement, distortion control for image accuracy, and dispersion reduction to prevent color fringing.  Optical solutions vary by design: aspherical lenses reduce spherical aberrations, Fresnel lenses are lightweight but can distort images, and Pancake lenses are compact and high-quality but more expensive. An Introduction To VR Optics A head-mounted display (HMD)—commonly referred to as a headset—projects signals from the display screen to the eyes through an optical system, creating a visual experience distinct from reality. Virtual Reality (VR) technology has rapidly advanced, immersing users in entirely virtual environments that feel like another world. At the core of VR display technology lies optical imaging, which projects virtual scenes to users’ eyes, enabling realistic visual experiences. Without an optical system, displays placed too close to the eyes would require constant diopter adjustments, leading to eye strain or damage. Moreover, if the display is closer than the eye’s focal adjustment range, imaging becomes impossible. VR optical systems address this by converting the near-eye display’s point light signals into approximately parallel light rays, minimizing diopter adjustment strain and creating a comfortable, immersive experience.   Early VR optical systems used single lenses, borrowing principles from simple eyepieces like magnifying glasses. However, modern VR systems must balance imaging quality, device size, and weight, leading to the development of specialized optical solutions. Indicators of VR optics Field of view Field of view (FOV) is a critical metric that directly impacts user immersion. FOV refers to the maximum visible area users can see when wearing a headset, defined as the angle between the edges of the field of view. If expressed in the form of an angle, the size of the field of view is the size of the angle between the field of view at the edge of the object and the eye, that is, the maximum visible range, which is called the field of view angle. The field of view angle is an important parameter to judge immersion, which defines the visible area that VR users can see when wearing a headset. A wider field of view allows for a more immersive experience, allowing users to truly be in a virtual environment. In VR optics, 90° FOV is considered to be the pass line for VR immersion experience, 120° FOV is generally considered to be the standard for achieving partial immersive experience, and 180° FOV is the standard for VR to achieve full immersion. Currently, most VR devices offer FOVs between 90° and 120°. EyeBox The EyeBox defines the range within which a user’s eyes can move while still perceiving the image clearly. For a comfortable experience, the EyeBox must accommodate eye movement and variations in user eye spacing. The entry pupil diameter of the human eye is approximately 4 mm, making this the minimum size for the EyeBox. When using VR devices, users usually move their eyes. And each person’s eye distance is different, and the condition of wearing the device is also different when using it. So the EyeBox should be as big as possible. Expanding the EyeBox improves comfort but complicates VR optical design and may impact other performance metrics.   Distortion VR optics transmits the virtual picture to the human eye through the optical system, and the human eye as the entrance pupil is outside the optical system, the system is asymmetric, and due to the large field of view requirements, the optical system often has more obvious distortion. Distortion occurs when the optical system transmits images with geometric inaccuracies, such as “pincushion distortion (pillow distortion),” where images stretch at the edges. Distortion is intrinsic to VR optical systems due to their asymmetrical design and large FOV requirements. Pre-processing images into a “barrel” shape compensates for distortion but reduces resolution. Improved optical designs can alleviate processing demands and enhance quality.  Illustration of Pincushion and Barrel Distortion in VR Optics Dispersion Dispersion is a situation that most VR devices encounter when they are used, manifesting as color fringing, where different wavelengths of light (colors) diverge at the image’s edges. This is because the VR device transmits the signal to the human eye through refraction and transmission, so with the increase of the field of view, the vertical color difference will be more obvious. Off-axis light beam of different wavelengths is focused through the lens after the height of the plane is different, that is, the magnification of each wavelength after imaging is different, so the vertical axis color difference is also called the power color difference. The focal points of multiple wavelengths are sequenced in the direction of the height of the image plane, and the final visible edge of the image plane produces a rainbow band. Lens combinations with differing Abbe coefficients correct chromatic aberrations but increase cost and weight. Image pre-processing is another method to counteract dispersion. Other key indicators in VR optics include resolution, pupil spacing, entry pupil distance, volume, and weight, all of which influence the overall design and usability of the optical system. Optical solutions for VR devices Aspherical lens In theory, near-eye displays can be achieved using a single spherical lens. However, spherical lenses suffer from significant spherical aberration, resulting in poor imaging performance. Additionally, spherical lenses exhibit large field curvature, leading to poor image quality at the edges of the field of view. Spherical lenses also have fewer adjustable parameters, limiting their ability to address these issues effectively. The surface of an aspherical lens is irregular, with curvature that changes depending on the lens’s height. By adjusting aspherical parameters, spherical aberration can be eliminated, and field curvature minimized. This is particularly effective when both lens surfaces are aspherical, offering significantly better imaging quality compared to spherical lenses. Processing aspherical lenses is more complex than spherical lenses. While traditional precision polishing technology offers higher accuracy, it is time-consuming, expensive,

Key Takeaways Adaptive optics for microscopy improves image quality by correcting refractive aberrations in specimens, especially in deep tissue imaging.  Techniques involve sensors, deformable mirrors (DMs), and spatial light modulators (SLMs) to dynamically counteract distortions. DMs, ideal for broadband light, adjust with electrostatic or piezoelectric forces, while SLMs suit laser-based, wavelength-specific applications. Adaptive optics setups vary by microscope type, as aberration correction needs differ. Customized AO solutions allow users to optimize high resolution imaging for complex optical applications. There’s a promising new way to improve image quality and correct for the inevitable aberrations in high resolution microscopy.  Adaptive optics for microscopy. Choosing high quality optics enables you to improve your image quality and produce high resolution microscope images. But even if you’re working with optical components that are ideal and perfect in every sense, there are some aberrations that won’t go away. These are the aberrations caused by the spatial variations in the refractive index of the specimens being studied. The deeper the tissue being imaged, the worse the problem gets.  Adaptive optics involves a range of techniques that enable you to correct for these aberrations before the image is produced, making high-resolution and even super-resolution imaging possible in tissue as deep as tens or hundreds of micrometers. Here we’ll look at just how adaptive optics work to make high quality microscopy possible even with deep tissue imaging. Understanding Adaptive Optics for Microscopy How can you correct for aberrations caused by inhomogeneous samples and specimens with complex optical structures? The trick is to use optics that can transform themselves based on their environment, adapting on-the-go when faced with specific aberrations.   Dynamic aberration correction involves an optical system that includes a special sensor that measures aberration at different parts of the sample. This might, for instance, be a wavefront sensor. A sequence of measurements is used to optimize the aberration correction, and deformable mirrors (DMs) or liquid spatial light modulators  (SLMs) respond in real-time. These dynamic optics provide conjugate aberrations— equal but opposite—- to cancel out the problematic aberrations at each point on the sample. caption: This series of images demonstrates how adaptive optics for microscopy work to cancel out the aberrations caused by the nonuniform optical profile of the specimen. Choosing the Right Adaptive Optics for Microscopy Adaptive optics can work well in many types of high-resolution microscopes, from fluorescence  and multi-photon fluorescence microscopes to laser scanning microscopes and parallelism scanning systems. But it’s important to realize there’s no one plug-and-play adaptive optical solution that works in any microscope you might want to use. The adaptive system will need to be customized based on both the physical configuration of the microscope and the image formation process that is used.  Suppose you use a conventional wide field fluorescence microscope. In this microscope, the illumination path is used simply to illumine the sample in a uniform way, and aberrations are only a problem when it comes to the imaging path.  In a confocal microscope, however, aberration is problematic in both the illumination and imaging paths, and adaptive optics need to be set up to compensate in both areas.  But those are not the only two possibilities. In a two-photon excitation fluorescence microscope, the resolution is dependent on the illumination path, and it is here you might need adaptive optics: aberrations in the imaging path will have no effect on the final results. When using adaptive optics for microscopy with a confocal microscope, attention must be paid to both illumination and imaging paths. Comparing Adaptive Optic Elements When it comes to the actual optical elements within your AO microscopy system, you have two major options: liquid crystal spatial light modulators or deformable mirrors.  A deformable mirror is a dynamic optic manufactured with a reflective surface. The shape of this surface may be continuous or segmented, but either way is designed in such a way that it can be ‘deformed’ or changed by the application of tens to hundreds of actuators, which are acted upon by either electrostatic, electromagnetic, or piezoelectric forces. Deformable mirrors are polarization independent and typically provide high reflectance over a broadband. DMs are generally the best choice for fluorescence light and other weak emissions, or when multiple wavelengths of light must be corrected simultaneously. A spatial light modulator is wavelength dependent and can only be used with parallel light. There are different types of SLMs, but liquid crystal on silicon (LCOS), used in reflection mode,  is one frequently used option. Most SLMs have lower optical efficiency than DMs, but they are a good choice for many laser applications. There’s also a third possibility, which is not yet widely used in microscopes but may gain importance in the future: transmissive adaptive elements. A transmissive adaptive element is formed of transparent, fluid-filled chambers. The shape of these chambers can be dynamically altered to create the desired aberration. References Booth, M. Adaptive optical microscopy: the ongoing quest for a perfect image. Light: Science and Applications 3, e165 (2014). https://doi.org/10.1038/lsa.2014.46 Marx, V. Microscopy: hello, adaptive optics. Nature Methods 14, 1133–1136 (2017). https://doi.org/10.1038/nmeth.4508 Jingyu Wang, Yongdeng Zhang. 2021: Adaptive optics in super-resolution microscopy. Biophysics Reports, 7(4): 267-279. DOI: 10.52601/bpr.2021.210015 Booth, M. J. (2019). A basic introduction to adaptive optics for microscopy (1.0). Zenodo. https://doi.org/10.5281/zenodo.3471043 Related Content

Key Takeaways: Super High Durability optical coatings (SHD Optical Coatings) enhance IR window performance with high transmission efficiency, scratch and chemical resistance, anti-reflective properties, and environmental resilience.  Designed for aerospace, military, and industrial applications, SHD coatings maintain signal clarity in harsh environments, resist abrasion and chemical exposure, and withstand temperature fluctuations.  Compared to conventional coatings, SHD coatings extend the lifespan and reliability of IR systems, making them essential for demanding operational conditions in high-stakes fields. In the realm of optical technology, where precision, durability, and high performance are paramount, Super High Durability (SHD) coatings stand out as essential advancements. SHD coatings are engineered specifically for infrared (IR) windows, meeting the need for enhanced durability, efficient transmission, and strong environmental resistance. They find widespread use in aerospace, military, and industrial applications, where IR systems endure harsh conditions. This article explores the critical features of SHD coatings, highlighting their significance and benefits over conventional coatings. Key Characteristics of Super High Durability Coatings SHD optical coatings possess distinct properties that enable high performance under challenging conditions. Here are their core characteristics and technical composition: Optical Coatings 1. High Transmission Efficiency Efficient IR transmission is crucial for systems like infrared windows, and IR-guided equipment, where clarity and signal strength are crucial. – Material Composition: SHD coatings use materials with high transparency within IR wavelengths, particularly in the mid-wave infrared (MWIR) range of 3–5 μm and the long-wave infrared (LWIR) range of 8–12 μm. Materials such as zinc sulfide (ZnS), zinc selenide (ZnSe), and IR-compatible glasses are common in SHD coatings due to their favorable transmittance properties. – Layer Optimization: Constructed with multiple layers optimized to minimize reflection by matching refractive indices between the coating, substrate, and environment, these coatings reduce light loss and ensure minimal interference. – Application Significance: High transmission efficiency is indispensable in applications where signal quality is vital, such as thermal sensors, IR spectroscopy, and military-grade targeting systems. 2. Durability SHD coatings withstand abrasive and chemically aggressive environments, making them ideal for industrial, aerospace, and defense applications. – Abrasion and Scratch Resistance: By incorporating ultra-hard materials like diamond-like carbon (DLC), SHD coatings provide a robust, scratch-resistant surface suitable for abrasive environments. – Chemical Resistance: Equipped with chemical-resistant layers, SHD coatings shield IR windows from substances like acids, alkalis, and solvents—critical in industrial and military settings where exposure to fuels and cleaning agents is common. – Adhesion Strength: Techniques like ion beam-assisted deposition (IBAD) and plasma-enhanced chemical vapor deposition (PECVD) enhance adhesion, creating a stable, durable finish that extends the lifespan of IR systems. 3. Anti-Reflective Properties Reducing surface reflection is essential in infrared optics, where even minor losses can disrupt imaging. – Reflection Minimization: SHD coatings incorporate multi-layer anti-reflective (AR) structures that alternate between high- and low-refractive-index materials. These layers work synergistically to counteract reflection losses, ensuring more IR light passes through the window with minimal reflection. – Enhanced Imaging: By lowering surface reflections, SHD coatings improve the signal-to-noise ratio in IR systems, resulting in clearer and more accurate imaging. This enhancement is especially beneficial in thermal sensors, where precise imaging quality is essential for effective target detection and monitoring. Optical components with coating Silicon Dioxide and Titanium Dioxide Coating Lenses 4. Environmental Resistance SHD coatings provide strong resistance to temperature fluctuations, humidity, water, and particulate exposure, making them suitable for extreme environments. – Temperature Resistance: Tolerating temperatures up to 300–500°C, depending on the substrate, SHD coatings are suitable for aerospace and high-temperature applications where thermal stability is critical. – Humidity and Water Resistance: Treated with hydrophobic and oleophobic layers, SHD coatings repel water and resist humidity, maintaining clarity in moist environments, which is valuable in outdoor surveillance or meteorological applications. – Dust and Debris Resistance: Certain SHD coatings incorporate anti-static layers that repel dust, which is particularly beneficial in environments like manufacturing plants, where airborne particles are prevalent. This feature minimizes the need for frequent cleaning, maintaining clear optical pathways and extending the service life of IR windows. Technological Applications and Market Significance SHD coatings provide benefits across multiple industries: – Aerospace and Defense: In military-grade systems like missile guidance, thermal imaging, and target acquisition, SHD coatings deliver consistent performance and reliability, enhancing mission success rates and equipment longevity. – Industrial Monitoring and Environmental Control: Industrial applications rely on SHD-coated IR windows for high-temperature monitoring and emissions control in harsh environments, where resilience to abrasion and chemicals is critical. – Medical and Scientific Research: In medical and scientific fields, SHD coatings support accurate IR spectroscopy and thermal imaging by maximizing transmission and minimizing interference from environmental factors. These qualities are essential in applications like non-invasive diagnostics and detailed spectroscopic analysis. Comparing SHD Coatings with Conventional Coatings While conventional coatings are effective in standard conditions, they may lack the durability required in harsh IR applications. Standard anti-reflective coatings may degrade under high abrasion or chemical exposure. SHD coatings, by contrast, are tailored for infrared wavelengths and constructed to withstand physical and environmental stresses, offering superior transmittance, durability, and environmental resistance, ultimately enhancing IR systems’ service life and performance. Conclusion SHD optical coatings represent a sophisticated solution for infrared windows, enabling durability and resilience in demanding environments. With high transmission efficiency, scratch and chemical resistance, anti-reflective capabilities, and environmental stability, SHD coatings play a critical role in defense, aerospace, and industrial applications. As industries demand greater reliability from IR systems, SHD coatings offer a transformational enhancement that ensures longevity and quality in the most challenging optical applications.  In essence, SHD coatings are more than an addition to IR windows—they are a vital advancement, ensuring consistent performance and reliability for today’s high-stakes optical technologies. Related Content

Key Takeaways: Hot and cold mirrors are dielectric-coated optics that selectively reflect or transmit infrared (IR) radiation, offering valuable heat management solutions.  Hot mirrors reflect up to 90% of near-IR (NIR) and IR light while transmitting UV and visible light. Conversely, cold mirrors reflect UV and visible light, transmitting up to 80% of NIR and IR.  These versatile optics can be tailored for various applications, such as beamsplitters or filters, and are essential in systems where thermal control is critical, including automotive displays.  Avantier provides custom solutions for diverse industries. Hot Mirrors and Cold Mirrors If you need to protect a delicate experimental setup from unwanted heat, you may need a hot mirror or a cold mirror.  Hot mirrors and cold mirrors are versatile optics designed to separate infrared radiation from other light. They are typically multilayer dielectric mirrors, and can be manufactured in a variety of different substrates and configurations. In this article we’ll look at hot mirrors and cold mirrors and just how they accomplish their purpose. Before we finish, we’ll go through a comparison of their technical features that can help you decide which mirror is best for you.  Hot Mirrors Hot mirrors reflect as much as 90% of NIR and IR light while transmitting up to 80% of UV and visible light. Depending on the experimental setup, the reflected heat may be directed toward a heat sink or alternative component that can make use of the energy, or simply away from any delicate components that should be protected from heat. Hot mirrors can also be used as bandpass filters or beamsplitters. The image below shows a typical transmission curve for a hot mirror.  Transmission curve of a hot mirror. Note the steep change in transmission, an important feature of both hot mirrors and cold mirrors. A custom hot mirror can be designed to perform best at any specific angle of incidence between  0° and 45°. Typically, either a 0° or 45° angle of incidence is chosen.  Cold Mirrors Cold mirrors do the same job as hot mirrors do— separating UV and visible light from NIR and IR—- but they do it the opposite way. Instead of reflecting IR light and transmitting visible, they reflect 90% of UV and visible light while transmitting as much as 80% of NIR and IR light.  Because of this, a reflectance curve for a cold mirror looks very similar to a transmittance curve for a hot mirror— you just need to remember you’re looking at two different features. Compare the image below with the transmission curve of the hot mirror above. Reflectance curve or a typical cold mirror. An incident angle of  0° and 45°— or any angle in between- can be chosen when a cold mirror is designed. It’s also possible to design a cold mirror that transmits UV light and only reflects the visible spectrum.  Just like hot mirrors, cold mirrors can be used as beamsplitters or bandpass filters, with a laser beam, for instance. You can even use hot and cold mirrors together, set up in conjunction, to pass visible light and block UV, IR, and NIR. One modern use of cold mirrors is the heads up display in an automobile. Cold mirrors are used to project the visible image to the viewer, while transmitting NIR and IR away from the system to eliminate heat buildup and image distortion.  Comparison of Hot Mirrors and Cold Mirrors Hot and cold mirrors are very similar in many ways, including their applications. Both are dichroic filters; mirrors manufactured with carefully customized dielectric coatings on glass substrates. Both can be manufactured to any desired angle of incidence, from 0 to 45. And both can be used to separate IR and NIR light from visible and UV wavelengths.  Deciding whether you want to go with a hot mirror or cold mirror often comes down to decisions about the preferred beam path in your optical system. Would you rather set up a mirror so that the unwanted light is reflected out of your system, or would you rather it was transmitted away?  Comparison of hot and cold mirrors . There’s one more important technical difference between the two types of mirrors. While a hot mirror reflects 90% of NIR and IR light while transmitting up to 80% of visible, a cold mirror transmits up to 80% of IR or near IR light while reflecting up to 90% of the visible spectrum. If you need to isolate a full 90% of NIR and IR light, you will need to work with a hot mirror. Similarly,  if 80% of visible light transmittance is not enough for your application, you’ll need to use a cold mirror.  Hot Mirrors and Cold Mirrors at Avantier At Avantier we produce custom hot and cold mirrors for customers in research, industry, medicine and defense. Our team of optical engineers and designers are available to work with you on your optical application, and state of the art manufacturing equipment allows us to produce almost any component in-house.  Throughout the optics world, we’re known for going the extra mile to ensure our clients are fully satisfied. Contact us today to get started with your own design project or custom order.  Related Content

Key Takeaways Optical prisms are versatile glass components used to manipulate light in various applications, from laser alignment to microscopy.  This optical prism selection guide outlines key prism geometries, such as right-angle, roof, and equilateral prisms, and their primary functions, including deviation, inversion, and dispersion. It highlights applications in fields like spectroscopy, medical imaging, and satellite communication.  Additionally, the guide discusses the importance of substrate selection based on light wavelengths and environmental conditions. Avantier offers a variety of prism options for diverse optical needs, ensuring precision and efficiency. Optical Prisms Selection Guide Optical prisms are solid glass optical components that can be used to manipulate light in many ways. From the minuscule dove prism in an endoscope to the porro prism in a space telescope, prisms can be found in many widely varying optical systems. Chosen wisely they can lead to more efficient, compact design and higher image quality.  But just how do prisms work, and what prism is best for your application?  This selection guide will provide an overview of the different geometries you may see in prisms, complete with details about prime applications and key functionalities. Knowing whether you need dispersion, deviation, displacement or rotation will help you decide what prism type is best for you.  You should also be aware that prisms can be made of various substrates, and the substrate that is best for you will depend on the specific wavelengths of light you are targeting and the environmental conditions in which you work. Your Selection Guide to Optical Prisms Right Angle Prism A right angle prism is the basic geometry you probably think of when you think of a prism— a neat triangle wedge that deviates a ray path by 90°. These prisms are also called 45° – 90° – 45° prisms. 45° – 90° – 45° prisms are often used in combination to displace an image or beam.  The standard way to use a right-angle prism is with light entering through one leg and exiting through another. The image you get is left-handed.  But if you change the orientation relative to the incident beam so that light enters through the hypotenuse, your prism is called a porro prism. The light will bounce against both legs and exit through the same side, the hypotenuse. This results in a right-handed image.  The right angle prism is one of the simplest in this optical prism selection guide, and is used for both deviation and displacement. Applications of right angle prisms include: Laser Alignment Medical Instrumentation Telescopes Microscopy Endoscopy Primary Functions: Deviation and Displacement Roof prism A roof prism looks like the roof of a house, just the way you might have drawn it back in elementary school. Total internal reflection on the ‘roof’ enables this prism to bend light by 90 degrees even while inverting it. There are a number of types of roof prisms, each with slightly different geometries; one common type is the amici roof prism. The amici roof prism gives a right handed image. A roof prism is an effective way to combine deviation and inversion. Applications of roof prisms include: Spotting scopes Microscopes Telescope Eyepieces Binoculars Primary Functions: Deviation and Inversion Equilateral prism If you think of a prism as a bit of glass that turns light into rainbows, you’re thinking of an equilateral prism. An equilateral prism will have three 60 degree angles and is used primarily to disperse light into its primary colors.  An equilateral prism has three matching sides. Applications of equilateral prisms include; Spectroscopy Telecommunications Laser light separation Primary Functions: Dispersing light into its component wavelengths.  Dove Prism There are two kinds of dove prisms; one with a reflective coating and one without. The uncoated version rotates a prism by twice the prism rotation angle and produces a left handed image. The coated version reflects a beam back onto itself, and produces a right handed image.  Both types of dove prism look the same; like a right angle prism with one corner truncated or cut off.  A dove prism may be used for pattern recognition. Applications of dove prisms include; Imaging around corners Interferometry Medical imagery Astronomy Primary Functions: Rotation, inversion, retroflection.  Penta Prisms A pentaprism, as its name suggests, has five faces. Two of these faces are at a ninety-degree angle to each other, and when incident light enters one of these faces it will emerge from the other, having been deviated 90°. Since the image is neither inverted nor reversed, these prisms are a favorite choice for many imaging applications. Penta prisms can reflect light precisely. Applications of penta prisms: Display systems Plumb level and surveying  Spectroscopy Metrology equipment Projection Visual targeting Cinephotography Primary function: Deviation Retroreflectors Retroreflectors are also called trihedral prisms or corner cube reflectors; they reflect any beam that enters the prism face and sends it back at an 180 degree angle. The image resulting from a retroreflector is left handed. Retroreflectors have many applications, and they aren’t all earth-bound.  When the Apollo 11, 14, and 15 landed on the moon, the astronauts left retroreflectors behind. Scientists on Earth aimed lasers at the prisms and, through time of flight calculations,  were able to calculate precisely the Moon’s orbit and shape. Retroreflectors work well even when precise alignment is impossible. Applications of retroreflectors: Satellite communication Laser tracking Precise alignment Rangefinding Free space optical communications Boresighting Interferometry Primary function: Deviation and displacement Light Pipe Homogenizing Rods Light pipe homogenizing rods are a special kind of prism that hardly looks like a prism at all. And rather than scatter light, these prisms make it tidier—- more homogenized. These square or hexagonal pipe-shaped prisms are also known as waveguides, light funnels, homogenizing rods or light guides.  Light enters a waveguide through one end, and is kept within the prism with total internal reflection till it is emitted at the other end.  These light funnels are often used to transform the light from  non-uniform sources into clear, homogenized light.  Light Pipe Homogenizing Rods are highly effective at homogenizing

Key Takeaways Ultra broadband metallic mirrors provide high reflectivity over a wide wavelength range (UV to NIR), outperforming standard metallic mirrors that only reflect well within narrower ranges.  These mirrors are ideal for multi-purpose systems, offering flexibility, durability, and high damage thresholds.  They perform consistently across various angles of incidence and are suited for applications like photon counting, hyperspectral imaging, and Raman spectroscopy.  Ultra Broadband Metallic Mirrors Sometimes, standard metallic mirrors can’t reflect as much light as you need. That’s when you turn to an ultra broadband metallic mirror. Broadband dielectric or metallic mirrors are excellent choices for many general-purpose applications, offering both performance and value. A good broadband mirror may suffice for applications requiring reflectivity from the UV to visible range or from visible to NIR. However, if you need high reflectivity from UV to NIR, an ultra broadband metallic mirror is what you want—a high-performance optic specifically designed to deliver superior results over a wide wavelength range. Thin metallic coatings—typically aluminum, gold, or silver—are enhanced with specialized dielectric coatings to boost reflectivity, ensure optimal surface quality, and provide critical protections. An ultra broadband metallic mirror is designed with some key properties that make it essential for many spectrometry applications. Here we’ll look at some of the differences between ultra broadband metallic mirrors and other standard metallic mirrors. We’ll also have a brief look at some of the important applications of ultra broadband mirrors and why this specialized mirror is key to the high performance needed. What Sets Ultra Broadband Metallic Mirrors Apart The most obvious feature of ultra broadband metallic mirrors is their wide wavelength range. Standard metallic mirrors, in contrast, are optimized for a much narrower wavelength range. You might have a UV mirror or an IR mirror, depending on what you need it for.  A third mirror might be designed for high reflectance in the visible. However, an ultra broadband mirror can reflect across all of those ranges. High reflectivity or enhanced reflectance is another key feature of ultra broadband metallic mirrors. While other optical mirrors may have reflectivity as high as 99%, this is only true over a very narrow band. Outside this narrow wavelength, reflectivity drops drastically. An ultra broadband mirror, however, typically has average reflectivity of greater than 85 % up to 97.5 % for a broad spectral range. The exact reflectance depends on the design of the mirror. This graph illustrates the difference in reflectance profile between an ultra broad band and a broadband mirror with average reflectivity. Ultra broadband mirrors also offer more application flexibility compared to their non-ultra broadband counterparts. They may be an excellent choice for multi-purpose systems capable of working with different wavelengths of light. Applications like broadband lasers, spectroscopy, and imaging may all benefit from these versatile mirrors. These mirrors are not just designed to reflect well over a wide range of wavelengths; they are also engineered to perform consistently at a wide range of angles of incidence. This is a contrast to standard metallic mirrors, where performance tends to degrade at angles other than normal incidence. Another advantage is their durability. The careful engineering that goes into these specialized mirrors includes protective coatings against oxidation, heat, and moisture, often resulting in a high damage threshold. Applications of Ultra Broadband Metallic Mirrors High-performance ultra broadband mirrors are used in various applications, particularly when broadband reflectance is required or when an optical setup needs to accommodate different light frequencies. Key applications include photon counting, hyperspectral imaging, and Raman spectroscopy. In photon counting, light is relayed through a system, and individual photons are detected by a single-photon detector. Because these counters are highly sensitive, mirrors with very high reflectivity over all relevant bandwidths are essential. One notable use of photon-counting techniques is in medical scanning, where these systems enable ultra-high resolution CT imaging with minimal radiation exposure. Simplified diagram of a photon counting setup, one of the applications of ultra broad band metallic mirrors. Ultra Broadband Metallic Mirrors at Avantier At Avantier, we produce custom ultra broadband metallic mirrors as well as other custom optics upon request. Whether you need a specialized mirror for photon counting,  Raman spectroscopy, or a Ti sapphire laser, we’ve got you covered. Contact us today for more information or to set up an initial consultation.  References Remy-Jardin, M., Hutt, A., Flohr, T., Faivre, J. B., Felloni, P., Khung, S., & Remy, J. (2023). Ultra-High-Resolution Photon-Counting CT Imaging of the Chest: A New Era for Morphology and Function. Investigative radiology, 58(7), 482–487. Sorokin, S. Naumov and I. T. Sorokina, “Ultrabroadband infrared solid-state lasers,” in IEEE Journal of Selected Topics in Quantum Electronics, vol. 11, no. 3, pp. 690-712, May-June 2005 Related Content