Multi-octave anti-reflection coating for polypropylene-based quasi-optical devices

The sensitivity requirements of modern CMB instruments place high demands on the use of low loss materials for filter, lens and window devices. Anti-reflection coating (ARC) designs are routinely used to effect minimal dielectric fringing over a limited waveband, however there is a need to maximize this bandwidth over the operating range of the instrument. Here we present the design, manufacture and testing of prototype polypropylene devices based on multiple layer ARCs, to effect high transmission over three octaves of frequency.