Short- and Long-pass Filters

Sharp Slopes at the Edge

Short-pass filters and long-pass filters are also known as edge filters. Typically, this type of filter is characterized by a short transition between the passband and the blocked wavelengths. The wavelength that separates the absorption and transmission ranges is also known as the edge. Short-pass filters transmit wavelengths that are shorter than the edge wavelength. Longer wavelengths are blocked. Longpass filters, on the other hand, transmit long-wave radiation and block the shorter wavelengths.

Edge filters are used wherever it is required to optically separate specific spectral ranges from each other.

Interference filters show a much steeper edge than color glass filters.