Linear Variable Filter

We’ve combined patented short wave pass and long wave pass Linear Variable Filters (LVF) to create an adjustable bandpass filter.  By adjusting the intersecting positions of the 2 LVFs, you can adjust both the center wavelength and bandwidth. Each filter features an excellent transmission band and strong blocking band with versions available for Visible (VIS 400-700nm), Near Infrared (NIR 550-1000nm), and Ultraviolet (UV 300-330nm).

These filters — with interference coatings applied to 60 mm x 15 mm quartz substrates — are especially useful for spectrally shaping the excitation energy from broadband sources used for fluorescence.

Linear Variable Filters | Bandpass – VIS, NIR, UV

PIXELTEQ’s Linear Variable Bandpass Filters are precision coated filter pairs with a center wavelength that changes linearly down the length of the rectangular substrate. The center wavelength of the bandpass filter can be adjusted simply by moving the filter’s position relative to the light source. The bandwidth of the bandpass filter can be adjusted by moving the pair of filters relative to each other – adjusting the long wavelength pass and short wavelength pass filters to widen or narrow the bandwidth.

Linear Variable Bandpass Filters are available in VIS (visible range, 400-700nm), NIR (near infrared range, 550-1000nm), and UV (ultraviolet range, 300-330nm) versions. These high performance filters deliver strong transmission and robust blocking.  Blocking can be further improved by adding a second linear variable filter.  The precision filters are coated on fused silica substrates for minimal auto-fluorescence and durable performance.

A single Linear Variable Bandpass Filter can replace multiple fixed filters in compact, non-dispersive instruments that require measurement at multiple specific wavelengths across the range. Each of the filters can also be used separately as a long wavelength pass or short wavelength pass linear variable filter.

Benefits

• Continuously variable wavelength selection in one filter
• UV (230-500nm), VIS (400-700nm) and NIR (550-1000nm) versions
• Enable instrument design versatility & range
• Scalable to high volume OEM production

Applications

• VIS and NIR spectroscopy
• Biomedical instruments
• Fluorescence measurement
• Remote sensing
• Air & water quality
• Order sorting filters
• Monochromators
• Flexible prototyping

Linear Variable Filters | VIS Short Wave Pass & Long Wave Pass Filters

VIS (visible range) short wave pass (340-850nm) and long wave pass (310-850nm) linear variable filters are also available individually with respective cutoff and cut-on positions that vary down the length of the filters.  Each filter combines strong average transmission (~88% for short wave pass and ~92% for long wave pass) with robust blocking that averages 0.01% out-of-band.

LVFs can be used to spectrally shape the excitation energy from a single broadband source.as opposed to using multiple light sources with various wavelengths or a front-end scanning monochromator.