Skip to content 
812/34nm Near Infrared Band Pass Filter
812/34nm Near Infrared Band Pass Filter is designed to transmit light centered at 812nm and FWHM 34nm. Coligh is a manufacturer of custom optical filters.
It has features below:
- Center wavelength 812
- FWHM 34nm
- Transmission above 90%
- Blocking depth OD>=6
- ION Assisted Hard Coaring
Products Categories
Get A Free Quote
Hard-Coated 812nm NIR Bandpass Filter with 34nm FWHM Description
812/34nm near infrared band pass filter Coligh manufactures is a high-performance optical filter based on multilayer dielectric film interference technology, designed for spectrally selective transmission in the 812 nm near infrared band.
- The central wavelength is 812+/-1nm, which is a common band for near infrared biological tissue transmission window, semiconductor material characteristic spectrum and industrial sensing.
- Full width at half maximum (FWHM): 34 nm, passband range is 795–829 nm, 34 nm narrow bandwidth effectively suppresses adjacent band interference and improves system spectral resolution.
- We achieve narrowband high transmission and deep blocking by hard plating ion-assisted coating. In the 795-829nm passband range, the transmittance is greater than or equal to 90%. The cut-off depth OD>=6 in the range of 350-1000nm outside the passband, with extremely deep blocking band and wide spectrum suppression
812/34nm Near Infrared Band Pass Filter Technical Datasheet
| Parameter | Specification |
| Center Wavelength (CWL) | 812nm ± 1 nm |
| Full Width at Half Maximum (FWHM) | 34nm± 1 nm |
| Peak Transmission | 90% |
| Blocking Range | 350-1000nm |
| Optical Density (OD) | OD ≥ 6 outside passband |
| Angle of Incidence (AOI) | 0° +/-5° |
| Surface Quality | 60/40 scratch-dig (per MIL-PRF-13830B) |
| Material Substrate | Fused Silica JGS1 |
| Coating Type | Hard-Coated Interference Filter/ IAD Assisted Coating |
| Thickness | 1mm (typical) |
| Filter Dimensions | Custom sizes available (e.g., Ø12.5 mm, 60×60 mm) |
| Clear Aperture | >90% of physical size |
| Operating Temperature | -40°C to +85°C |
812/34nm Near Infrared Band Pass Filter Applications
- Industrial detection
Plastic sorting requires the identification of specific polymers through near-infrared spectroscopy. ABS has a characteristic absorption peak at 812 nm, but the spectral overlap of mixed plastics will reduce the sorting accuracy. The 812/34nm bandpass filter can be integrated into the spectral sensor of the sorting machine, and with the 812 nm LED light source, it only receives the 795–829 nm reflection signal. : The 34 nm narrowband focuses on the ABS absorption peak and suppresses the 780–800 nm interference signals of polyethylene and polypropylene. And it blocks the visible light and infrared heat radiation in the workshop - Medical equipment
Non-invasive hemoglobin detection is based on the absorption characteristics of deoxyhemoglobin at 812 nm, but skin melanin and tissue scattering will reduce the signal accuracy. This filter can be built into the optical probe of the monitor and work synchronously with the 812 nm LED light source to extract the target absorption signal. Narrowband filtering suppresses ambient light and improves the stability of dynamic monitoring. - Research field
The fluorescence emission peak of quantum dot PbS/CdS is near 812 nm, and the Rayleigh scattering and stray light of the 532nm laser excitation light need to be filtered out. This filter can be placed in the collection light path of the spectrometer as a supplement to the long-pass filter to isolate the 795–829 nm fluorescence signal. - Material science
The thickness of optical films can be accurately measured by 812 nm laser interferometry, but the multi-wavelength reflection of the substrate material will interfere with the interference fringes. The 812/34nm filter can be embedded in the laser interferometer to allow only 812±17 nm interference signals to pass through and shield stray light of other wavelengths. Control the reflection noise of the substrate material in the visible light band and improve the contrast of the interference fringes
