Optical Characterization of a Highly Multimoded Bolometer

Abstract

Highly sensitive bolometers have become standard tools for probing the cosmic microwave background (CMB). Recent efforts by ground and balloon based detectors have focused on making measurements of the polarization of the CMB in order to test inflationary models. Most of these detectors have used arrays of single-moded bolometers in various frequency bands. One way to obtain increased sensitivity in a next-generation detector is to use a multimoded bolometer architecture, where each pixel couples to dozens or hundreds of modes. We will review the operational principles of the basic bolometer detector for conducting measurements of the CMB and discuss the relative advantages of a multimoded architecture. We use this background to discuss the Multimoded Survey Experiment (MuSE), a proposed CMB polarization experiment which uses highly multimoded bolometers. We then present an optical characterization of one of the detectors for MuSE by measuring and analyzing the bolometer’s response to time-varying and polarized optical signals.