<title>Recent advances in miniaturization of infrared spectrometers</title>

Abstract

In the past ten years, a number of miniature spectrometers covering the visible and near infrared wavelengths out to 2.5 microns wavelength have been developed and are now commercially available. These small but high performance instruments have taken advantage of continuing advances in high sensitivity detectors--both CCD's and diode arrays, improvements in holographic gratings, and the availability of low-loss optical materials both in bulk and fiber form that transmit at these wavelengths and that can readily be formed into monolithic shapes for complex optical structures. More recently, a number of researchers have addressed the more intractable problems of extending these miniaturization innovations to spectrometers capable of operation in the mid-infrared wavelengths from 3 microns to 12 microns and beyond. Key enabling technologies for this effort include the recent development of high D*, uncooled thermopile and micro-bolometer detector arrays, new low- mass, high-efficiency pulsed infrared sources, and the design and fabrication of novel monolithic optical structures and waveguides using high index infrared optical materials. This paper reviews the development of these innovative infrared spectrometers and, in particular, the development of the `wedge' spectrometer by Foster-Miller, Inc. and the MicroSpec<SUP>TM</SUP>, a MEMS-based solid state spectrograph, by Ion Optics, Inc.