Angular dispersion of double-diffraction grazing-incidence spectrograph

Haim Lotem; Mordechai Lando; Avraham Lorber; Dan Manor

doi:10.1117/12.281350

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22 September 1997 Angular dispersion of double-diffraction grazing-incidence spectrograph

Haim Lotem, Mordechai Lando, Avraham Lorber, Dan Manor

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Proceedings Volume 3110, 10th Meeting on Optical Engineering in Israel; (1997) https://doi.org/10.1117/12.281350
Event: 10th Meeting on Optical Engineering in Israel, 1997, Jerusalem, Israel

Abstract

Utilization of linear array detectors in spectroscopy enables efficient and fast spectral data accumulation of entire spectral bands. The dependence of wavelength on the location along the detector is thus, a pertinent issue in modern spectroscopy. We discuss the behavior of the angular spectral dispersion of plane grating spectrographs in double- diffraction grazing-incidence geometry, and compare it to Littrow mounting. In the Littrow case, the dependence of the dispersion on wavelength is almost linear for narrow spectral bands, but the slope depends on wavelength. In contrast, in a double-diffraction grazing-incidence spectrograph the dispersion deviates strongly from linearity with wavelength. However, relative to the diffraction angle at a reference wavelength, (lambda) _G, the shape of the dispersion curve in the band of maximum dispersion is, to a first approximation, constant and independent of the spectrograph wavelength setting. The reference wavelength is the one that is propagating normal to the plane folding mirror in the spectrograph, and it may be tuned by rotating the mirror. This characteristic of the dispersion is an important advantage in the calibrating process of the instrument.

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Haim Lotem, Mordechai Lando, Avraham Lorber, and Dan Manor "Angular dispersion of double-diffraction grazing-incidence spectrograph", Proc. SPIE 3110, 10th Meeting on Optical Engineering in Israel, (22 September 1997); https://doi.org/10.1117/12.281350

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