845nm Bandpass Filter

845nm light falls in the near-infrared (NIR) spectrum, offering high sensitivity with minimal visible light interference and good transmission through certain materials like plastics and biological tissues.

  • Application 1: In optical sensing systems for detecting organic compounds or moisture content in food products, where 845nm light interacts uniquely with target molecules for accurate measurements.
  • Application 2: In short-range infrared communication devices (e.g., IR data links or remote control systems) to isolate the 845nm wavelength, ensuring reliable signal transmission and reducing interference from ambient light sources.
  • Application 3: In biomedical applications such as pulse oximetry or tissue oxygenation monitoring, where the filter enables precise capture of 845nm light absorption by hemoglobin, aiding in non-invasive health parameter measurement.
  • US20080097198A1 - Lymph Node Detector

    US20080097198A1 - Lymph Node Detector

    Context: A medical fluorescence imaging device designed to locate sentinel lymph nodes during surgery using a fluorescent dye (typically Indocyanine Green).

    Usage of Filter: The 845nm bandpass filter is installed in the imaging head, positioned directly in front of the CCD or CMOS image sensor.

    Function: It serves as an emission filter that blocks the excitation laser light (typically around 780nm) and exclusively transmits the fluorescence emission which peaks at 845 nm.

    Result: This provides the surgeon with a high-contrast, real-time image where only the lymph nodes glow against a dark background, enabling precise surgical targeting and minimizing tissue removal.

  • US20220171105A1 - Resonant filters having simultaneously tuned central wavelengths and sidebands

    US20220171105A1 - Resonant filters having simultaneously tuned central wavelengths and sidebands

    Context: A nanophotonic device utilizing Guided-Mode Resonance (GMR) technology to create ultra-compact optical filters for telecommunications or sensing.

    Usage of Filter: The filter is constructed as a single-layer grating waveguide structure (a "meta-surface") rather than a thick stack of many layers.

    Function: It uses sub-wavelength grating parameters to induce a resonance mode that allows light at exactly 845 nm to pass through with a "flat-top" spectral profile.

    Result: The device achieves a box-like transmission spectrum with steep sidewalls in a very thin form factor, improving signal fidelity for narrowband applications without the bulk of multi-cavity Fabry-Perot filters.

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