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638/12nm Interference Filter Optics
638/12nm Interference Filter Optics is designed to transmit light centered at 638nm and FWHM 12nm. Coligh manufactures EUV to IR bandpass interference filter.
- Center wavelength 638nm
- FWHM 12nm
- Transmission peak ≥90%
- Blocking depth OD6
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638nm Hard-Coated Narrow Bandpass Interference Filter Description
638/12nm interference filter is a narrow bandpass filter designed based on the principle of optical interference. Its core function is to selectively transmit light with a specific wavelength of 638nm center wavelength and 12nm half-width FWHM, while deeply blocking light in other bands.
- The center wavelength is 638+/-1nm, optimized for the red light band, suitable for 630-650nm lasers and fluorescent dyes Cy5, Alexa Fluor 647, accurately transmits 638nm signals, suppresses background light, and is especially suitable for weak light detection
- The narrow band half-width is 12+/-1nm, ensuring high spectral resolution and effectively separating target signals from background noise.
The transmittance in the passband is greater than or equal to 90%, maximizing the retention of signal strength. - The OD in the non-passband range of 350-1000nm is >=6, completely suppressing the interference of stray light.
- We use hard multi-layer coating and ion-assisted coating technology, which is resistant to high temperature, high humidity and scratches. It is suitable for complex and harsh environments, extends service life and reduces maintenance frequency.
638/12nm Interference Filter Optics Technical Datasheet
| Parameter | Specification |
| Center Wavelength (CWL) | 638nm ± 1 nm |
| Full Width at Half Maximum (FWHM) | 12nm± 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 |
638/12nm Interference Filter Optics Applications
- Biomedical imaging
638nm is a common excitation wavelength for far-infrared fluorescent dyes such as Cy5 and Alexa Fluor 647, but the autofluorescence of biological samples at 500-600nm will interfere with the target signal. The 638/12nm narrowband filter can be placed at the front end of the detector as an emission filter for fluorescence microscopes or flow cytometers. The transmitted dye emission light blocks the 638nm excitation light reflection signal at the same time. It makes deep tissue imaging clearer, and can also be combined with 488nm and 561nm filters to achieve multiple fluorescence synchronous detection. - Raman/fluorescence spectrometer
In Raman spectroscopy detection, the signal excited by 638nm laser is easily submerged by Rayleigh scattering, and background noise needs to be filtered out efficiently. The 638/12nm filter can purify the laser light source to ensure the monochromaticity of 638nm. Block Rayleigh scattered light and only transmit Raman scattered signals - Laser processing equipment
638nm red laser is often used for precision processing, but the plasma radiation or ambient light generated during the processing will interfere with the laser sensor. This filter can be installed at the laser output head or the sensor receiving end as a laser purification or protection filter. It transmits 638nm working laser, blocks stray light of 300-620nm and above 650nm, avoids false triggering of laser control signals, and ensures consistency of processing position. - Agricultural optical biosensing
The photosynthesis efficiency of plants can be evaluated by chlorophyll fluorescence dynamics. 638nm red light can excite chlorophyll fluorescence, but multi-band interference in natural light needs to be filtered out. The 638/12nm narrowband filter can be embedded in the excitation and detection optical path of the handheld plant detector as a dual filter to provide pure 638nm light to excite chlorophyll. Collect 685nm fluorescence signals, block ambient light, detect crop stress in real time, and guide precision agriculture.
