Spatial Frequency Multiplexing in Spectroscopy

Spectroscopic imaging is a widely employed diagnostic approach with applications spanning several different disciplines. Although color-sensitive cameras are very common and used for everyday photography, scientific applications often require highly specific color sensitivity to avoid signal cross-talk and misinterpretations. Such systems are primarily based on sequential acquisition configurations and are, therefore, inherently slow and unsuitable for studies of living samples and rapidly progressing events. To address this problem, different means to acquire spectroscopic data rapidly have been developed. One such method is based on spatial frequency multiplexing, wherein the user either illuminates the sample with several intensity-modulated light fields or observes the response of the sample through optical components that modulate the light in space. If different spectral signal components are given unique modulation patterns, a camera can record several spectral images in parallel and thereafter separate them digitally. This chapter explains the fundamental principles of this technical solution and presents the progress made thus far.