High Reflectivity Mirrors

A high reflectivity mirror, often referred to as a supermirror, is a specialized type of dielectric mirror designed to achieve exceptionally high reflectivity while minimizing light scatter and absorption. These precision mirrors are crucial for various laser applications, including beam steering, folding, and interferometry. They find use in industries such as security, defense, medical research, and process control.

Here is an overview of high-reflectivity mirrors and their characteristics:

Types of High Reflectivity Mirrors

Laser Line Mirrors: These mirrors are designed to reflect and redirect a narrow band of light centered on the laser’s wavelength, or laser line. They are tailored for specific laser wavelengths and are commonly used in laser systems for beam manipulation.
Broad Band Mirrors: Broadband mirrors, on the other hand, offer reflectance over a wider spectral range. They are versatile mirrors suitable for applications requiring reflection across a broader range of wavelengths.

Both types of high-reflectivity mirrors are constructed using dielectric materials, consisting of multiple thin layers. Ion beam sputtering is a common technique used in the manufacturing process to achieve the desired reflectivity at specified wavelengths. To ensure high laser damage thresholds, high-quality fused silica substrates are often used in combination with durable reflective coatings.

Calculating Reflectivity of Supermirrors

Measuring the exact reflectivity of an ordinary mirror can be done using spectrophotometry, where transmission is measured and the reflectivity is inferred. However, for supermirrors with reflectivity levels exceeding 99.5%, the signal-to-noise ratio in spectrophotometry becomes problematic. In such cases, cavity ring-down spectroscopy (CRDS) is a more precise method for determining the exact reflectivity.

CRDS involves directing a laser pulse into a resonant cavity formed by two highly reflective mirrors being tested. As the laser light reflects within the cavity, some light is lost with each bounce. The total loss for each mirror can be determined by measuring the decay time of the reflected light.

This method accounts for all forms of light loss, including transmission, absorption, and scatter, providing a more accurate assessment of reflectivity.

Custom High Reflectivity Mirrors at Avantier

Avantier produces high-reflectivity mirrors with a focus on exceptional performance and quality. These mirrors feature super-polished substrates and high surface quality to ensure optimal performance in demanding applications.

Quality control measures at Avantier include CRDS to verify the exact reflectance of every supermirror. In addition to reflectance, the company’s in-house metrology equipment allows for the measurement of various optical properties, including surface quality, flatness, absorption, polarization characteristics, and laser damage thresholds.

Avantier offers a range of high-performance supermirrors in stock, including options with mirror mounts. They also provide the flexibility to produce custom high-reflectivity mirrors tailored to specific customer specifications.

If you have unique requirements for high-reflectivity mirrors or need mirrors for specialized laser applications, you can contact Avantier to discuss manufacturing limits or custom specifications.

Factory Standards

Surface Quality	20-10 S/D
Material	from DUV to IR
Best R	>99.995% @laser wavelength
Custom wavelengths	HR-266nm, HR-355nm, HR-532nm, HR-1064nm, HR-1550nm

Avantier can produce custom high-reflectivity mirrors to meet your exact specifications for a variety of applications. Please contact Avantier to schedule a consultation or request a quote for your next project.