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809/20nm Narrow Optical Filter
809/20nm Narrow Optical Filter is a narrow bandpass filter to transmit 809nm and blocking other wavelength. Coligh manufactures EUV to 30000nm bandpass filters
- Center Wavelength 809nm
- FWHM 20nm
- Tp>90%
- OD4 deep blocking depth
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809/20nm Narrow Optical Filter Description
809/20nm narrowband optical filter is a bandpass filter designed for precise selection of 809nm ±10nm optical signals.
- The central wavelength is 809nm+/-2nm, and the half bandwidth is 20+/-2nm. It only allows optical signals in the range of 799–819nm to pass efficiently, effectively shielding interference from other bands.
- The transmittance in the target band is greater than or equal to 90%, achieving ultra-low light energy loss and ensuring maximum signal strength
- The cut-off depth outside the passband is within 200-1200nm, effectively shielding interference from other bands
- We use interference hard coating technology and high-quality optical glass, such as sapphire, K9 or colored absorption glass, to reduce the light scattering and autofluorescence interference of the material itself while ensuring strong film adhesion, scratch resistance and long life.
809/20nm Narrow Bandpass Optical Filter Technical Datasheet
| Parameter | Specification |
| Center Wavelength (CWL) | 809 nm ± 2 nm |
| Full Width at Half Maximum (FWHM) | 20 nm ± 3nm |
| Peak Transmission | ≥ 90% |
| Blocking Range | 200 – 1200nm |
| Optical Density (OD) | OD4 |
| Angle of Incidence (AOI) | 0° |
| Clear Aperture | >90% of the diameter |
| Substrate Material | UV Fused Silica, K9,sapphire, Other optical glass |
| Size | Ø12.7mm, Ø25.4mm,Ø50.8mmor customizable |
| Environmental Durability | Compliant with MIL-STD-810G |
| Other avaliable wavelength | 809/10nm, 809/40nm |
| Custom Option | EUV to 30,000nm |
| Filter Type | Multilayer Interference Bandpass Filter |
| Coating Technology | Ion-Assisted Deposition (IAD), Hard coated |
| Surface Quality | 80-50, 60-40, 40-20 (per MIL-PRF-13830B |
809/20nm Narrow Optical Filter Applications
- Biomedical imaging
In biological fluorescence imaging, the target molecule is usually excited by light of a specific wavelength and emits a slightly longer wavelength fluorescence signal. However, the excitation light 809nm is close to the wavelength of the fluorescence signal. Traditional wide-band filters are difficult to completely separate the two, resulting in the image being interfered by strong excitation light and a low signal-to-noise ratio. Whether used as an emission filter or an excitation filter, the 809/20nm bandpass filter can ensure the purity of the signal and light source, making the separation of the fluorescence signal and background noise more thorough - LiDAR
The LiDAR system measures distance by emitting 809nm laser and receiving reflected signals. However, ambient light will drown out weak reflected signals, resulting in short detection distance and reduced accuracy. The 809/20nm narrowband filter only allows 799-819nm laser echoes to pass, which can suppress wide-spectrum background light such as sunlight - Industrial detection
In industrial detection, 809nm lasers are often used to illuminate the object to be measured, and defects or foreign objects are identified by reflected/transmitted light characteristics. However, the ambient light of the production line is complex, and the material itself may reflect multi-band stray light, leading to misjudgment. The 809/20nm optical filter can only collect characteristic reflection signals near 809nm and shield interference from other wavelengths.
