905nm Bandpass Filter

905nm bandpass filters are designed to transmit a selected near-infrared band centered near 905nm while reducing unwanted out-of-band light.

Applications:
- 905nm pulsed laser diode source cleanup
- LiDAR, rangefinding, and time-of-flight receiver filtering
- NIR LED illumination and machine vision
- Detector-side 905nm signal isolation before silicon photodiodes, silicon APDs, CMOS sensors, or NIR receivers
- Broadband NIR source filtering for sensing, inspection, or optical measurement

Bandwidth options:
- 6nm and 10nm FWHM for narrow 905nm laser signal isolation
- 20nm and 30nm FWHM for LiDAR or receiver-side filtering with more return-signal collection
- 40nm, 50nm, 55nm, and 85nm FWHM for NIR LED illumination, machine vision, or broader NIR signal collection

Select the bandwidth based on the laser or LED spectrum, detector sensitivity, ambient background, blocking range, and required signal level.

905 nm pulsed laser diode

Use CWL 905 nm with 6–10 nm FWHM for 905 nm laser diode line selection, source cleanup, or narrow isolation of a 905 nm laser signal.

905 nm pulsed laser diodes are commonly used in rangefinding, optical sensing, and time-of-flight systems. For laser-line filtering, the key specs are CWL near 905 nm, FWHM such as 6 nm or 10 nm, high transmission at 905 nm, and OD blocking across the unwanted wavelength range.

905 nm NIR LED or LED array

Use CWL 905 nm with 30–55 nm FWHM for NIR LED illumination, source cleanup, or practical 905 nm-region output.

905 nm LEDs have broader emission than laser diodes, so medium or broad filters are usually more practical than very narrow filters. Use 30–40 nm FWHM when the setup needs stronger wavelength selection around 905 nm. Use 50–55 nm FWHM when the system needs more usable NIR output.

Broadband NIR source

Use CWL 905 nm with 30–85 nm FWHM to select a practical NIR band from tungsten-halogen, xenon, supercontinuum, or other broadband NIR sources.

For broadband NIR illumination or testing, the filter extracts a 905 nm-centered band from a wider spectrum. Use 30–40 nm FWHM when the setup needs a more defined NIR band. Use 50–85 nm FWHM when higher transmitted signal is more important for illumination, imaging, or detection.

Machine vision and NIR imaging

Use CWL 905 nm with 40–85 nm FWHM for machine vision or NIR camera imaging when the goal is broad 905 nm-region contrast rather than strict laser-line isolation.

For CMOS or CCD camera imaging, wider 905 nm-region filters can provide more usable signal for inspection, alignment, and contrast enhancement. Important specs include CWL, FWHM, transmission, and blocking of visible or unwanted NIR light that may reduce image contrast.

Detector-side 905 nm signal isolation

Use CWL 905 nm with 6–30 nm FWHM before a silicon photodiode, silicon APD, CMOS/CCD camera, or spectrometer input when the target signal is near 905 nm.

For detector-side filtering, the filter passes the 905 nm signal while reducing background outside the target band. Use 6–10 nm FWHM when stronger wavelength isolation is needed. Use 20–30 nm FWHM when signal throughput is more important.

US 11,280,884 B2 - LIDAR Instrument and Method for Operating

Context: A LIDAR instrument designed for autonomous vehicles or mapping systems that must operate effectively in high-solar-radiation environments (daylight).

Usage of Filter: The filter is configured as a "matching filter" with a narrow passband (5 nm or less) placed immediately before the detector.

Function: It is specifically tuned to a "solar blind" or atmospheric absorption window where solar radiation is naturally attenuated by water vapor in the atmosphere, while passing the specific 905 nm laser wavelength.

Result: This achieves a high Signal-to-Noise Ratio (SNR) by exploiting both the filter's rejection of broadband sunlight and the atmosphere's natural attenuation of background noise at that specific wavelength band.

US 8,309,926 B2 - Pulsed-laser beam detector with improved sun and temperature effects compensation

Context: A pulsed-laser beam detector used in laser rangefinders, speed detectors, and LIDAR jammers that require high sensitivity to weak return pulses.

Usage of Filter: The filter is used at the optical input aperture to strictly limit the spectral bandwidth of light reaching the photodiode array.

Function: It acts as a spectral gate that blocks "foreign" laser sources (e.g., 1550 nm or 1064 nm) and significantly reduces the total optical power from ambient sunlight and heat sources entering the receiver.

Result: Prevents receiver saturation and allows the system's "Automatic Threshold Circuit" (ATC) and variable gain amplifiers to focus amplification solely on the 905 nm signal, improving detection range and accuracy.

US 2025/0208328 A1 - Optical Filters with Hydrogenated Silicon Carbide

Context: Advanced wide-angle LiDAR and 3D sensing systems requiring optical filters that maintain performance even when light enters at steep angles (High Angle of Incidence).

Usage of Filter: The 905nm filter is constructed using alternating layers of Hydrogenated Silicon Carbide (SiC:H) (high refractive index) and Silicon Oxide (low refractive index).

Function: The SiC:H material provides a high refractive index (approx. 3.46), which minimizes the "blue shift" (spectral shift toward shorter wavelengths) that typically occurs when interference filters are tilted or receive light from wide angles.

Result: Ensures the filter maintains high transmittance of the 905 nm signal across a wide Field of View (FOV), preventing the signal loss at the edges of the image that occurs with standard filter materials.

Need Help Choosing a Product?

Share your requirement of spectral or your application goal.We will review and provide product recommendation to you.