Dielectric edge filters provide a sharp transition in transmission which is used to separate two wavelength regions. Long wave pass filters are designed to transmit wavelengths longer than 50% of the cut-on values, while rejecting the shorter wavelengths. Short wave pass filters will transmit wavelengths shorter than their 50% cut-off value and reject longer wavelengths.

CVI Optical Components offers a full line of long and short pass dielectric filters from the ultraviolet to the far infrared. The average pass band transmission is typically better than 90% and less than 0.1% in the rejection zone, dependent on the substrate, angle of incidence and the spectral regions.

Wide bandpass dielectric filters with bandwidths above 15% usually are obtained by combining long and short pass filters. The following charts represent a cross-section of our production capabilities. All optical filters can be optimized according to the individual specifications.

Long pass filter - visible		Short pass filter - visible
Tave>90% 400nm to 700nm, Tabs<0.1% below 350nm. Cut-on slope < 4% For indices 1.45-1.90. Can be shifted and optimized for non-normal angles of incidence		Tave>85% 450nm to 600nm. Tave<1.0% 675nm to 1000nm. Cut-off slope < 5% Higher rejection values are achievable with a slight loss in the transmission characteristics
Long pass filter on Ge		Short pass filter on sapphire
Tave>90% 8µm to 12µm, Tabs<0.1% below 6.5µm Can be applied to most IR substrates. Comparable values are achieved in the 3µm to 5µm region		Tave>85% 3µm to 5µm, Tave<0.1% to far infrared Can be applied to most IR substrates. Comparable values are achieved in the far infrared region
Wide bandpass filter - visible		Wide bandpass filter - infrared
Tave>80%, Tmin>70% in the pass band Different bandwidth values available		Tave>80%, Tmin>70% in the pass band Tave<0.1% from UV to far infrared

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