Optical Long Pass Filter Dyes
The spectrum of light is divided into three major sections. The Ultraviolet region goes from about 200nm to 400nm. The visible region goes from about 400nm to 750nm. The infrared region goes from about 750nm to 2000nm. This catalog includes formulations of our dyes which have been developed to be incorporated into polymers, such as acrylics and polycarbonate, to fabricate optical long pass filters used in a variety of applications. At present, we can develop filters with windows or cut-offs from 350nm to 1000nm.
Because our dyes provide a sharp cut-off, from 0% transmission to 100% transmission, the filter exhibits excellent sensitivity to wavelength shifts. The sensitivity approaches that of glass filters.
Models are used to develop these formulations. This technology allows us to experiment with many combinations of dyes to get the optimum performance profile.
Long pass used in a variety of applications. These include: precision spectroscopy applications as band separators. In photometry applications long and short pass filters are used as order sorting or blocking filters, which are applied to a detector’s window to eliminate any second- and third-order distortion. Long and short pass filters are also frequently used in Raman spectroscopy.
When selecting long pass and short pass filters, it is important to consider three different specifications related to the product’s wavelength ranges: cut-on / cut-off wavelength, transmission range, and rejection range. A filter’s cut-on / cut-off wavelength is typically represented as a single wavelength, such as “700 nm.” Barrier filters are also commonly referred to by their cut-on wavelength; for example, a “700 nm long pass filter” cuts off at 700 nm and passes all wavelengths (light) higher than this.