Optical Bandpass Filter

Bandpass filters, like those from Avantier, are essential optical components. They transmit a specific range of wavelengths while blocking others, finding use in biotech, laser separation, and more. These filters are specified by parameters such as Center Wavelength, Peak Transmission, FWHM, Pass Band Ripple, and Edge Steepness. Types include All-Dielectric, Metal-Dielectric, Multiband, and Narrowband filters. In electronics, active bandpass filters process signals in a defined frequency range. Avantier offers both standard and custom bandpass filters for various optical applications, ensuring tailored solutions to meet specific needs.

Optical Bandpass Filters
Optical Bandpass Filters

Optical Bandpass Filters

Purpose of Bandpass Filters

  • Bandpass 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


  • 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.


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