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30 January 2002 Large-area silicon immersion echelle gratings and grisms for IR spectroscopy
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We present design examples for instruments making use of micromachined silicon grisms and immersion gratings. The capabilities of high index grisms, transmission grating-prism hybrids, open up new possibilities in compact IR spectrograph design with spectral resolving power, R~500-5000. Coarsely grooved immersion gratings will provide for unique high resolution spectrograph designs in the near and mid-infrared (resolving power, R~104-105). The high refractive index of silicon shortens the required grating depth, to produce a given resolving power, by up to a factor of 3.4. Alternatively, at a given resolving power, an immersion grating can allow a spectrograph slit to be widened by this factor relative to an instrument using a grating illuminated in air or vacuum; this increases the instrument sensitivity without degrading the spectral resolution. Our analysis here illustrates the potential of these devices to improve spectrograph throughput, spectral resolution, and wavelength coverage while reducing the required instrument volume relative to similar instruments using non-immersed diffraction gratings and low index prisms and grisms.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Luke D. Keller, Daniel T. Jaffe, Oleg A. Ershov, and Jasmina P. Marsh "Large-area silicon immersion echelle gratings and grisms for IR spectroscopy", Proc. SPIE 4485, Optical Spectroscopic Techniques, Remote Sensing, and Instrumentation for Atmospheric and Space Research IV, (30 January 2002);

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