Correction of RAC phase response by Langmuir-Blodgett films

Abstract

The correction of the phase versus frequency characteristic of SAW (surface acoustic wave) RAC (reflecting array compressor) and ILRAC (in-line RAC) pulse compressors using Langmuir-Blodgett films (LBFs) is reported. Without recourse to photolithography, an accurate, stepped thickness profile is easily deposited, correcting a position-dependent velocity error. The equations giving the required LBF profile are presented, and the limitation of LBF thickness to a positive, integer number of molecular layers is allowed for. Experimental results are presented of a device in which simulated compressed pulse sidelobes are reduced by 19 dB.<>