Manufacturing of monolithic and butcher block filter arrays for earth observation applications

Abstract

Multispectral earth observation is done using selected discrete filter channels. The optical filtering is typically accomplished using optical thin film filters. These filters can be placed in filter wheels or as an array directly in front of the detector. For compact system designs filter arrays are preferred. The manufacturing of filter arrays can be done by two different approaches called monolithic array and butcher block. Typical optical requirements for such filters are for example a filter transmission of above 90% and an out-of-band blocking in OD6 range.