Optical Bandpass Filters

Bandpass filters, like those from Avantier, are essential optical components that transmit a specific range of wavelengths while blocking others. These interference filters are widely used in biotech, laser separation, and high humidity environments. They are specified by parameters such as center wavelength, peak transmission, FWHM, passband ripple, and edge steepness. Using thin-film technology, Avantier offers a wide variety of bandpass filters, including all-dielectric, metal-dielectric, multiband, and narrowband filters. In addition, band-blocking and bandpass filters play a critical role in electronics, where active filters process signals in a defined frequency range. All filters are mounted for durability and precision. Avantier provides both standard and custom solutions for diverse optical applications, ensuring tailored results to meet specific needs.

Purpose of Bandpass Filters

Band pass filters allow the transmission of a specified range of wavelengths with high efficiency while blocking unwanted wavelengths.
Applications include biotech, machine vision, laser line separation, spectral radiometry, and fluorescence applications.

Specifications of Bandpass Filters

Key specifications include:

Center Wavelength (CWL): The wavelength at the center of the passband.
Peak Transmission (T): The maximum transmission wavelength.
Full Width at Half Maximum (FWHM): The bandwidth at 50% of maximum transmission.
Pass Band Ripple: Describes the flatness of the passband.
Edge Steepness: Indicates how quickly transmission drops off at the cut-off wavelengths.

Types of Bandpass Filters

All-Dielectric Bandpass Filters: Designed with alternating high and low refractive index materials and a dielectric spacer. Properties depend on the number of reflective mirror layers and spacer thickness.
Metal-Dielectric Bandpass Filters: Utilize metal spacers and are primarily used for UV bandpass filters.
Multiband Filters: Have multiple passbands, used to combine multiple light beams and correct color blindness.
Narrowband Filters: Provide high transmission over a narrow passband and block other light effectively, commonly used for clean-up and reducing cross-talk.

Bandpass Filters for Signal Processing

In electronics, active bandpass filters are used in signal processing to pass a certain frequency range while blocking others.
Active bandpass filters are often second-order filters and have a peak frequency response at the center frequency of their passband.
The bandwidth and quality factor are key parameters in describing bandpass filter characteristics

Custom Optical Bandpass Filters

Avantier offers a range of standard bandpass filters with varying specifications.
Standard filters cover the 400-1100 nm range, with sizes from 2-90 mm.
Custom bandpass filters can be produced to meet specific application requirements.

Avantier provides a wide range of bandpass filters suitable for diverse optical and photonic applications. Whether you require standard filters or have custom requirements, they offer solutions to address your needs. Please contact Avantier to discuss your specific bandpass filter needs, request a catalog of their stock filters, or inquire about custom options.