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Spectrometer Accessory · Order-sorting filter

Linear variable long-pass filter

Linear Variable Long-Wave-Pass Filter

An ion-sputtered quartz filter whose long-wave-pass cut-off shifts continuously along its length. Mounted in front of the detector of a fibre spectrometer it blocks the higher diffraction orders of the grating across the whole spectrum at once.

41.4 × 9.5 × 1 mm

Standard size

Quartz

Substrate

Linear Variable Long-Wave-Pass Filter
Best for: Suppressing second-order diffraction in fibre spectrometers covering more than one octave.

Features

  • Cut-off wavelength varies linearly along the filter
  • Ion-sputtered coating on a quartz substrate: minimal autofluorescence, high laser-damage threshold
  • Fits before the line-scan CCD of a fibre spectrometer

Applications

  • Higher-order diffraction cut-off in spectrometers

Technical Specifications

Linear variable long-pass filter Specifications

Specifications

TypeLinear variable long-wave-pass filter
SubstrateQuartz, ion-sputtered coating
Standard size41.4 × 9.5 × 1 mm
Position in the spectrometerContinuously variable order-sorting filter in front of the line-scan detector, after the grating and focusing mirror

We confirm sizes, variants and compatibility with your spectrometer before quotation.

Figures

Drawings, Photos and Measured Data

Transmission test curves of the linear variable long-pass filter at several positions
Measured long-wave-pass transmission at positions along the filter

Configure the Linear variable long-pass filter for your measurement

Tell us the wavelength range, the resolution you need and what you are measuring; we will propose the grating, slit and accessories to match.