Realization of the Hadamard Multiplex Advantage Using a Programmable Optical Mask in a Dispersive Flat-Field Near-Infrared Spectrometer

Abstract

Spectrometry and hyperspectral imaging are nding numerous applications for micro-optoelectrom echanical systems (MOE MS). A type of MOE MS device in the form of a digital micromirror array (DMA) has been m ade commercially available by Texas Instruments USA for projector display applications. We use this device as a spatial light modulator (SLM) in a new type of at-eld, nearinfrared dispersive spectrometer (NIRDM AS). Attributes of the DMA used in this manner are presented for discussion. Features that make a DM A attractive for spectrometry and imaging are describ ed. A brief introduction to H adamard transform (HT) techniques is presented to show that the DMA may be the best Hadamard encoding mask yet developed. A com parison of a conventional raster scanning (CRS) scan and a Hadamard transform spectrometry (HTS) scan with respect to the Hadamard multiplex advantage using a nonphoton noise-limited, single-element detector is presented. A signal-to-noise ratio comparison using four spectral lines from a m ercury-argon calibration lamp demonstrates that the theoretical noise reduction is approached for the HTS scan com pared to the CRS scan. Some future applications of M OEMS in spectrometry and hyperspectral im aging are suggested.

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