365nm Bandpass Filter

The 365nm light, belonging to long-wave ultraviolet (UVA), exhibits strong material penetrability and fluorescent excitation properties, capable of triggering luminescence in specific fluorescent substances while eliminating visible light interference.

Available Bandwidth Options

  • BP365-3 (3nm FWHM) - Ultra-narrow bandwidth for exceptional spectral selectivity, OD >6 blocking, ideal for precision fluorescence microscopy and Raman spectroscopy
  • BP365-8 (8nm FWHM) - Narrow bandwidth for high-precision UV applications
  • BP365-10 (10nm FWHM) - Mercury line optimized with OD5 blocking, perfect for semiconductor inspection and DAPI fluorescence
  • BP365-15 (15nm FWHM) - Research-grade precision for UV spectroscopy and laser line filtering
  • BP365-20 (20nm FWHM) - Moderate bandwidth with >85% peak transmission, cost-effective for machine vision and analytical instrumentation
  • BP365-30 (30nm FWHM) - Balanced performance for general UV applications
  • BP365-40 (40nm FWHM) - Medium bandwidth optimized for semiconductor defect detection and photolithography
  • BP365-90 (90nm FWHM) - Wide bandwidth for maximum light collection, ideal for mercury i-line and broadband UV detection
  • US Patent 7 098 469 - Forensic Light Source Kit

    US Patent 7,098,469 - Forensic Light Source Kit

    Context: This patent describes a portable forensic light source used by crime scene investigators to detect evidence that is invisible under normal light, such as bodily fluids, hair, and fibers.

    The Bandpass Filter is used as: A Source Clean-Up / Excitation Filter.

    Function: Standard UV bulbs and LEDs often "leak" a significant amount of visible violet/purple light. This filter is placed over the 365nm light source to block that visible purple leakage while transmitting the invisible UV energy.

    Result: It achieves High Contrast Fluorescence. By eliminating the visible purple "background noise," faint fluorescent evidence (like a fingerprint treated with dye or a trace of saliva) glows brightly against a totally dark background, making it visible to the investigator.

  • Light Sources for getting 365nm

    365nm Laser or 405nm Laser?

    Finding a true 365nm laser (as opposed to a standard UV flashlight) is actually quite specialized because most "UV lasers" sold consumer-side are actually 405nm (violet). True 365nm light is deep in the ultraviolet spectrum and is often used for high-end forensics, mineral validation, and laboratory curing.

    When searching, be careful with products labeled "UV Laser Pointers" for $10–$20 on sites like eBay or Amazon.

    • The Trap: Almost all of these are 405nm (violet light). 405nm is much cheaper to produce but doesn't "excite" fluorescent materials nearly as well as 365nm.
    • The Difference: A true 365nm light is nearly invisible to the eye until it hits a fluorescent object (which then glows brightly). 405nm looks like a bright purple laser beam.

    How to "Tighten" the Spectrum

    If your application requires an even narrower band than the standard 10nm FWHM (for example, in high-precision lab microscopy), you can use a ZWB2 Filter or a Bandpass Filter.

    • ZWB2 Filter: A piece of "Black Glass" often found on high-end UV flashlights. It doesn't narrow the 365nm peak itself, but it aggressively cuts off any "tail" of visible light above 400nm, making the beam look "pure" and invisible to the eye.
    • Bandpass Filter: A specialized optical glass that can narrow the light down to a 2nm – 5nm window, though this will significantly reduce the total power output.

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