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618.5/25nm Optical Band Pass Filter
618.5/25nm Optical Band Pass Filter is designed to transmit light centered at 618.5nm and FWHM 25nm. Coligh manufactures narrow and wide band hard coating filter.
It has features below:
- Center wavelength 618.5
- FWHM 25
- Transmission above 90%
- Blocking depth OD>=6
- ION Assisted Hard Coaring
- Custom highly welcomed
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Visible Bandpass Filter 618.5nm FWHM 25nm Description
618.5/25nm Optical Band Pass Filter Coligh manufactures is a high-performance optical filter.
- Central wavelength 618.5+/-1nm, half bandwidth 25+/-1nm, accurately covers the 606nm–631nm spectral range, effectively filters out stray light in non-target bands, and ensures signal purity.
- The transmittance in the passband is greater than or equal to 90%, and the cut-off depth OD>=6 in the range of 350-1000nm outside the passband, achieving excellent spectral contrast and meeting high signal-to-noise ratio requirements.
- We use hard dielectric film and ion-assisted deposition technology to ensure the firmness of the film layer, high temperature and high humidity resistance, and adapt to industrial or outdoor applications.
- We use JGS1 as the substrate and support customization of substrate materials, such as B270K9, etc., and can provide round or square cutting. We can accept customization of filters of any band and bandwidth
618.5/25nm Optical Band Pass Filter Technical Datasheet
| Parameter | Specification |
| Center Wavelength (CWL) | 618.5nm ± 1 nm |
| Full Width at Half Maximum (FWHM) | 25nm± 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 |
618.5/25nm Optical Band Pass Filter Applications
- Fluorescence microscopy
The excitation/emission spectra of fluorescent markers Cy5 and Alexa Fluor 647 are concentrated in the range of 610–630nm. It is necessary to accurately extract the target fluorescence signal while shielding the excitation light source and other background stray light. The 618.5/25nm bandpass filter can be installed in the detection light path of the microscope. In conjunction with the dichroic mirror, only the 618.5±12.5nm fluorescence signal is allowed to pass through the detector, filtering out the light in the non-target band and improving the signal-to-noise ratio. - AR/VR display color calibration
AR/VR devices need to accurately restore specific colors. The 618nm red light can be used for virtual interface highlight prompts to avoid color deviation of the display or ambient light interfering with the user experience. The 618.5/25nm bandpass filter can be embedded in the color wheel or light source path of the near-eye display module to limit the output light wavelength range and realize real-time color correction in conjunction with the sensor, which can ensure the wavelength consistency of the displayed color and reduce the color difference perceived by the human eye. - Raman spectrum enhancement
The Raman signal is weak and easily submerged by laser Rayleigh scattering. It is necessary to filter out the main laser peak 532nm or 785nm at the detection end, and only retain the 618nm Raman shift signal. This filter can be installed in the collection light path of the Raman spectrometer as a supplement to the notch filter, secondary filtering of residual laser noise, further eliminating laser background noise, and improving the clarity of Raman peak recognition.
