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Optical filter

Infrared long wave pass filter

  • Product ID:Optical filter
  • QQ:64689385
  • Phone: +86 18601742282
  • Tel: +86-377-60399566
  • Email: sales@yukangphotonics.com
  • Time: 2020-10-17 09:49

Infrared long wave pass filter

Filters are made by adding special dyes to a plastic or glass substrate or by evaporating an optical film on the surface to attenuate (absorb) certain bands of light in a wave or by accurately selecting a small band through which to reflect or absorb other unwanted bands. By changing the structure of the filter and the matching parameters of the membrane structure, various spectral characteristics can be obtained, so that the filter can control, adjust and change the transmission and reflection state of light waves. Its advantages are: peak transmittance, flat band spectrum, excellent cutoff in a wide band range, and good wet temperature stability.
Yukang photonics specializes in the production of various high-end narrow-band filters, bandpass filters, infrared ultraviolet filters, dichroic filters, long-wave pass filters, short-wave pass filters, advanced optical coating equipment, mature physical hard film technology, fast delivery cycle, can meet your customized requirements.

Technical characteristics

Infrared long wave pass filter can cut off sharp light at specific wavelength. This filter is usually used for order classification, which can isolate a wide range of spectrum, transmit a large amount of required energy and cut off excess energy at the same time. These filters are made of an optical IR transmission substrate coated with a hard and durable dielectric film on the outer surface, which can resist general cleaning and be used for any high-quality optical components. They are particularly suitable for FTIR spectroscopy and thermal imaging applications.

The infrared band ranges from 780 nm to 14 um, including near infrared, mid infrared and far infrared. There are three bands: near infrared (code IR-A, wavelength 780 ~ 1500 nm, NIR), mid infrared (IR-B, 1500 ~ 6000 nm, Mir) and far infrared (IR-C, 6000 ~ 14000 nm, FIR).   

In terms of materials, near infrared filters include optical glass coating, colored glass and plastic infrared filters. In case of mid-far infrared, materials include Si, Ge, ZnSe, Sapphire, CaF2, etc.

According to the optical characteristics, there are long-wave IR long pass filter and band-pass IR bandpass filter.

For long-wave infrared filters, there are generally three manufacturing methods:

1) Made of colored glass, usually black. It absorbs visible light and allows infrared light to pass through. If you look at the sun through this infrared filter, you can still see a red sun. Suitable for infrared imaging.

2) Made by coating on optical white glass, this type is also called optical cold mirror, which looks silvery and looks like a mirror. If it is a filter of mid-far infrared, it should be coated on Si, Ge, ZnSe, Sapphire, CaF2 or Shi Ying glass.

3) Infrared plastic filter made of special plastic has black appearance. If you look at the sun through this infrared filter, you can also see a red sun. The material of this plastic can be PC or PMMA.

For band-pass infrared filters, they are all made by vacuum coating. The near infrared red outer filter is coated on white glass. The infrared filters with red color in the middle and far infrared should be coated on Si, Ge and other infrared materials.

Yukang Optoelectronics adopts the world's advanced coating equipment, and its products have the characteristics of accurate wavelength positioning, high transmittance and high cut-off depth. The wavelength of infrared filter covers 780nm-14000nm.

The basic parameters


                                   Infrared long wave pass filter


Si、GE、ZnS、ZnSe, Sapphire, CaF2, Quartz, etc.

  Size and specification

According to customer requirements

  Dimensional deviation:

+ 0/0.2 mm (Φ D;L×W)

  Thickness deviation


  Pass aperture

> 90%

  Surface mass



< 0.2mm

  Operating temperature

-40°C /+70°C

  Storage environment

Constant temperature ~23℃; And humidity < 40%

  Cut-off depth


  Incident angle


≥90%(According to customer requirements

              (The above figure is the transmittance curve of product samples for reference only)

Technical advantages

Product parameters are true and reliable, and accept data comparison from third-party agencies

Ultra-narrow band filter with the narrowest bandwidth of 2nm

With custom gradient band pass filter design r & d production capacity

We provide the customized service of infrared filter

It has the design and production capacity of 99.99% dielectric film mirror with reflectance >

Customizable up to five band pass filters

Ultra - steep transition zone filters can be customized

It has the ability of secondary customization of imported high-end filters

Development and production of microarray bandpass filters for CCD

It provides contactless laser cutting service for high-end filters

Choose us is to choose excellent professional quality, impeccable processing, high level quality guarantee and full chain attentive services.
Contact us and discover what sets us apart!

Want to customize it? Provide your parameters, drawings or 3D models, our team of excellent engineers will help you!