Longpass Filters with Cut-On Wavelength (Range) 400 - 500 nm and Size (mm) 25 mm dia.

Longpass filter spectral curveLong Wavepass Filters

A longpass filter or long wavepass filter (LP filter) is one that transmits at longer wavelengths and rejects shorter wavelengths. By design, the transition in a longpass filter between the 50% cut-on to rejection is quite sharp. This makes it much easier to separate excitation from emitted wavelengths without interfering with wavelengths of interest. Long wavepass filters are useful in applications where spectral noise reduction is important or for isolating a particular region of the spectrum.

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  • Available every 50nm from 500nm to 1500nm
  • Mounted in a black anodized aluminium ring
  • Can be used in combination with shortpass filters for custom bandpass filtering
  • Fine tune cut-on wavelengths by changing angle of incidence

  • Emission filters in fluorescence applications
  • Eliminate unwanted radiation over ultraviolet, visible, or infrared
  • Ideal for Raman spectroscopy
  • Order sorting filters
  • Astronomy applications to study IR radiation without visible light
  • Laser-induced fluorescence to isolate source radiation

Product SKUs

  • 500 nm Long Pass, 25 mm Dia.

    Typical Long Pass Filter Curve
    8 in stock
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    Long Pass Filter Specifications | LP-500-25

    Cut-On Wavelength

    500 nm

    Cut-On Wavelength (Range)

    400 – 500 nm

    Cut-On Tolerance

    ±3 nm

    Transmission Region

    Cut-on λ to 2.2 µ minimum

    Minimum Peak Transmission


    Slope (OD 0.3 to 4.0)



    10-4 Int. Min. / 10-5 Int. Avg.

    Blocking Range

    200 nm-Cut On λ

    Size (mm)

    25 mm dia.

    Size Tolerance

    +0.0/-0.2 mm


    6.3 mm

    Thickness Tolerance

    +0.0/-0.2 mm



    Clear Aperture

    21 mm


    Aluminum, Black Anodized

    Operating Temperature Range

    -20⁰ C to 75⁰ C

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