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738/20nm Narrow-band Interference Filter
738/20nm Narrow-band Interference Filter is designed to transmit light centerd at 738nm and FWHM 20nm. Coligh manufactures EUV to IR bandpass interference filter.
It has features below:
- Center wavelength 738nm
- FWHM 20nm
- Transmission above 90%
- Blocking depth OD>=6
- Ion-Assisted Thin Film Deposition Hard Coating
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738/20nm Thin Film Interference Filter Description
738/20nm Narrow-band Interference Filter Coligh manufactures is a high-precision optical filter based on advanced thin-film interference technology.
- We achieve ultra-high transmittance greater than or equal to 90% in the range of 728-748nm through a precisely designed dielectric film stacking structure
- Deeply suppress non-target bands, with a cutoff depth OD>=6 in the range of 350-1000nm
- We use ion-assisted coating to precisely control the thickness of the film layer to ensure that the center wavelength and FWHM remain strictly consistent, with a center wavelength of 738+/-1nm and FWHM of 20nm +/-1nm
- We use fused quartz with a low thermal expansion coefficient as the substrate. Fused quartz has extremely small wavelength drift in a wide temperature range and is suitable for long-term stable operation in complex environments.
- Hard coating makes the film surface scratch-resistant, has high adhesion, and is extremely stable, significantly reducing customer maintenance frequency and costs.
- We support customization of size, shape, angle and band, and can provide flexible customization services to accelerate customer product prototype building and product launch process.
738/20nm Narrow-band Interference Filter Technical Datasheet
| Parameter | Specification |
| Center Wavelength (CWL) | 738nm ± 1 nm |
| Full Width at Half Maximum (FWHM) | 20nm± 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 |
738/20nm Narrow-band Interference Filter Applications
- Food safety testing
Biogenic amines in spoiled seafood have characteristic fluorescence peaks at 738nm, which need to replace time-consuming laboratory testing. The 738/20nm filter can be embedded in a handheld fluorescence detector, and the sample can be excited with a UV LED light source to extract the target signal through the filter. This can eliminate the interference of scattered light from fat and water, and accurately capture the characteristic signal of spoilage. - Military camouflage identification
Military camouflage simulates vegetation in the visible light band, but the reflectivity difference in the 738nm near-infrared band is significant. The 738/20nm filter is carried on the multi-spectral reconnaissance system of the drone to generate a 738nm single-band image and compare the spectral characteristics of vegetation. The camouflaged target can be identified by the reflectivity difference. - Plant photosynthetic efficiency monitoring
The 738nm band reflects the activity of the photosystem I, and combined with 680nm, it can quantify the efficiency of light energy distribution. The 738/20nm bandpass filter can be embedded in the multi-spectral camera of the drone to dynamically capture the reflection spectrum of the crop canopy and separate the 738nm characteristic signal through the filter. Eliminate soil and water background interference and accurately evaluate the state of photosynthesis. - Laser precision welding
38nm fiber lasers need to filter out side mode noise to ensure output spectrum purity and welding accuracy. This filter can be embedded in the laser resonator as a wavelength selection element to suppress non-738nm spurious modes, compress laser line width, and improve energy concentration.
