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785nm Long Pass Filter For Raman
785nm long pass filter for Raman spectroscopy is used to block the 785 nm laser line and transmit Raman-shifted signals at longer wavelength. Coligh manufactures Raman filters.
- Laser wavelength 785nm
- OD>6 blocking depth
- Transition width <1.6nm from 785nm to 50% transmission
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785nm Optical Laser Long Pass Filter For Raman Description
785nm Optical Laser Longpass Filter is a longpass filter designed for 785nm laser Raman spectroscopy system. Its function is to efficiently filter out the Rayleigh scattered light of 785nm laser, while allowing Stokes and anti-Stokes Raman signals (long wavelength) to pass through with high transmittance.
- The cutoff depth of this filter at 785nm is OD>6, which suppresses the Rayleigh scattered light of 785nm laser by more than 99.9999%, and can collect weak Raman signals.
- In addition, the transmission width from 785nm to 50% transmission point is < 1.6nm, which retains the near-infrared Raman signal to the maximum extent.
- The transmittance at 788.9-1770.7nm is greater than >93%, covering the near-infrared band, supporting low-noise and high-sensitivity signal detection.
- We use ultra-low fluorescence fused quartz, and sapphire or infrared materials are optional to meet the wide spectrum requirements from ultraviolet to near-infrared.
- In addition, strict optimization of the angle of incidence, Cone half angle 0° and 0+/-2° angle of incidence, ensures the stability of the filter in precision equipment such as confocal microscopy systems.
785nm Long Pass Filter For Raman Technical Datahsheet
| Parameter | Specification |
| Laser Wavelength | 785 nm |
| Average Transmission (Tavg) | >93% (788.9-1770.7 nm) |
| Transmission Ripple | <2% (788.9-1770.7 nm) |
| Absolute Blocking Depth (OD) | >6 @785 nm |
| Average Blocking Depth (ODavg) | >6 @650-785 nm |
| Transition Width | <1.6nm (785 nm to 50% transmission point) |
| Angle of Incidence (AOI) | 0 ± 2 degrees |
| Cone Half-angle | 0 degree |
785nm Long Pass Filter For Raman Applications
- Biomedical deep tissue imaging in vivo
Because 785nm excitation light and near-infrared Raman signals penetrate deeper into biological tissues and can reduce scattering and absorption, 785nm longpass Raman Filter can be used for non-invasive detection of metabolite distribution in deep tissues of living animals or human bodies. - Material Science Semiconductor Wafer Inspection
Micron-level defects such as dislocations and impurities cause small displacements of Raman peaks, requiring extremely high signal-to-noise ratios. 785nm longpass Raman filters can suppress laser noise, highlight the silicon 520cm⁻¹ peak, and wide spectrum transmission supports multi-peak synchronous analysis, improve chip yield, and reduce waste losses - Pharmaceutical drug crystal form identification
Differences in drug crystal forms affect drug efficacy, but traditional methods are time-consuming and cannot be detected in real time. 785nm Raman longpass filters can suppress the fluorescence band of excipients, highlight the characteristic peaks of crystal forms, and high transmittance can shorten the detection time and adapt to the rhythm of the production line - Explosives detection
The residual signal of explosives is weak, and the complex environmental background interference is serious. The ultra-narrow transition bandwidth of the 785nm long-pass filter can retain the nitro vibration peak and can be integrated into handheld devices to support on-site screening.
