Linear Variable Edge Filters

Designed for both individual and combined use, short and long-wave Linear Variable Edge Filters allow for blocking and passing of targeted wavelengths. Used independently, the short-wave linear variable filter has a wavelength range of 330 - 750nm with an average transmission of 97% from 400 - 750nm. The long-wave linear variable filter has a wavelength range of 300 - 845nm and an average transmission of 97% across the entire range. When combined, Linear Variable Filters can operate as a laser-line filter or a variable bandpass filter with tunable center wavelength and bandwidth.

A linear variable filter has an interference coating intentionally wedged in one direction to create a linear shift of the center wavelength across the length of the substrate. This shift allows for the broad filtering capabilities demonstrated by the short and long-wave variable filters. Short and long-wave variable filters work inversely of one another: the short-wave variable filter passes light throughout the filter’s length until a blocking band is reached, whereas the long-wave variable filter blocks light until a transmission band is reached. Blocking and transmission bands are adjustable by reorienting the filter to the light source.

With its broad blocking and transmission range, a single linear variable filter can replace an entire filter set. When synchronized with a single moving grading spectrometer, combined long and short-wave linear variable filters reduce scattered light and harmonics. In addition, combined linear variable filters can be used as a single variable excitation filter for various fluorescence applications using white light sources.