405/8nn Optical Interference Filter
405/8nn optical interference filter is bandpass filter with center wavelength 405nm and FWHM 8nm. Coligh manufactures standard and custom optical filter.
- Center wavelength 405nm
- FWHM 8nm
- Blocking depth above OD5
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405/8nn Optical Interference Filter Description
405/8nm interference filter is a narrow bandpass filter that allows light with a central wavelength of 405nm to pass through while blocking light of other wavelengths.
- Coligh enhances the transmitted light near 405nm through interference design of multi-layer dielectric films, and reflects or absorbs visible light and near-infrared light through the film layer.
- We use fused quartz and optical glass materials, and the filter has a cutoff depth of OD5 in the range of 200-1100nm, which is very suitable for use in blood analyzers and other biomedical instrument.
405/8nn Optical Interference Filter Technical Datasheet
| Parameter | Specification |
| Center Wavelength (CWL) | 405 nm ± 1 nm |
| Bandwidth (FWHM) | 8 nm ± 1 nm |
| Transmission Range | 401 nm – 409 nm |
| Peak Transmission | ≥ 90% |
| Blocking Range | < 0.001% (OD5) from 200 nm to 1100 nm |
| Substrate Material | Fused silica / Optical glass |
| Surface Quality | 80-50， 60-40， 40-20 scratch-dig (per MIL-PRF-13830B) |
| Clear Aperture | > 90% of the diameter |
| Filter Diameter | Customizable (e.g., 12.5 mm, 25 mm, 50 mm) |
| Filter Thickness | 1.0 mm ± 0.1 mm (also availiable for other thickness) |
| Coating Type | Hard-coated, ion-Assisted coating |
| Angle of Incidence (AOI) | 0° (normal incidence) |
| Durability | MIL-C-48497A compliant |
405/8nn Optical Interference Filter Applications
405/8nm optical interference filter can be used in many application scenarios:
- Biomedical imaging
In confocal microscopy, the excitation wavelength of DAPI Hoechst fluorescent dye is 405nm. The high transmittance of 405/8nm filter can improve the brightness of imaging. The light sheet isolates the excitation light and captures the fluorescent signal. And the cutoff depth of OD5 can eliminate background fluorescence. In flow cytometer, 405nm laser can excite specific fluorescent dyes such as CFP, YFP, and the narrow bandwidth of 8nm can reduce the interference of cross-color. - Hematology analyzer
In the spectrophotometer module of the hematology analyzer, 405nm filter is usually used as the core component of the monochromatic light source. Hemoglobin has characteristic absorption peaks in the ultraviolet-visible light region (such as the Soret absorption band near 405nm). The 405/8nm optical interference filter can measure the absorbance change and calculate the Hb concentration. - Flow cytometer
In flow cytometer, a 405nm filter is usually used at the laser emission end to eliminate the wavelength noise of the laser output, and a bandpass filter is used at the detection end. When blood cells pass through the flow channel, the 405nm laser irradiates the cells to produce scattered light. The cell size, morphology and complexity can be determined by analyzing the intensity of the scattered light.
