Linear Variable Filters
May 2011Edmund Optics Inc.Request Info
BARRINGTON, N.J., May 6, 2011 — Edmund Optics has introduced its linear variable filters designed for individual and combined use for maximum versatility; they are available in long- and short-pass versions.
They are manufactured with an interference coating that is intentionally wedged in one direction, creating a linear shift of the center wavelength across the length of the entire substrate. The shift enables broad filtering capabilities.
The short- and long-wave filters work inversely to one another. The former passes light throughout the filter's length until a blocking band is reached, while the latter blocks light until a transmission band is reached. The blocking and transmission bands may be adjusted by reorienting the filter to the light source. Using its broad blocking and transmission range, a single linear variable filter can replace an entire filter set, rendering it economical and compact.
Linear variable filters enable blocking and passing of targeted wavelengths. When used independently, the short-wave filter has a range of 330 to 750 nm with average transmission of 97% from 400 to 750 nm. The long-wave filter has a wavelength range of 300 to 845 nm and an average transmission of 97% across its entire wavelength range for maximum efficiency. Both provide blocking of OD >4. When they are combined, they can operate as a laser-line filter or as a variable bandpass filter with a tunable center wavelength and bandwidth for a vast array of applications.
To reduce scattered light and harmonics, combined long- and short-wave linear variable filters may be synchronized with a single moving grade spectrometer. Combined filters also can be used as a single variable excitation filter for a wide variety of fluorescence applications using white-light sources.