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Optical Filters-Optical Bandpass Filters

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What are optical bandpass filters?

Optical bandpass filters are optical filters that allow signals between two specific frequencies to pass, but that discriminates against signals at other frequencies.

Here is a spectrum curve of optical filter bandpass type:

What specifications are required for a optical bandpass filter?

  1. Center Wavelength(CWL) : the midpoint of passband wavelength
  2. Full Width at Half Maximum (FWHM): the width of the transmitting region at half of the maximum transmission value
  3. Blocked Area :the wavelength band that you want to block/reject
  4. Blocking Value: optical density
  5. Peak Transmission (Tpeak): the maximum transmission of the filter

Types of optical bandpass filters based on FWHM：

  1. Wide bandpass filter – uv wide bandpass filter , visible wide bandpass filter , ir wide bandpass filter
  2. Narrow bandpass filter – uv narrow bandpass filter , visible narrow bandpass filter , ir narrow bandpass filter

When the FWHM is larger than 30nm ,we normally determine the filter as a wide band pass filter. When the FWHM is smaller than 30nm,we determine the filter as a narrow band pass filter.

Types of optical bandpass filters based on wavelengths:

  1. UV bandpass filter / Ultraviolet bandpass filter
  2. VIS bandpass filter / Visible bandpass filter
  3. IR bandpass filter / Infrared bandpass filter

Applications of optical bandpass filters:

  • Medical
  • Laser range/distance measurement
  • Iris recognition
  • Automotive sensor
  • Industrial safety system
  • Biotechnology
  • Microscopy/Fluorescence microscopy

About Optolong customize bandpass filters

Optolong Optics offers a wide variety of bandpass filters for Ultraviolet , Visible , Infrared applications . The FWHM is from 3nm (ultra narrow band pass filter) to 100nm or even wider than 100nm. Sell the best custom optical bandpass filter is 650nm bandpass filter, 850nm bandpass filter, 940nm bandpass filter.

  • Profession Optical Bandpass Filters Manufacturer
  • IAD Hard Coating Technology
  • Dielectric High Precision Nanometer Film Coating
  • Narrowband High Transmittance Depth OD
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