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WIDEBAND SPECTRAL DISPERSER MADE OF ZnS FOR EXOPLANET CHARACTERIZATION USING SPACE-BORNE TELESCOPES

  • Enya, Keigo (Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency) ;
  • Fujishiro, Naofumi (Koyama Astronomical Observatory, Kyoto Sangyo University)
  • Received : 2015.06.29
  • Accepted : 2016.10.20
  • Published : 2017.03.31

Abstract

We present the development of a spectral dispersion device for wideband spectroscopy for which the primary scientific objective is the characterization of transiting exoplanets. The principle of the disperser is simple: a grating is fabricated on the surface of a prism. The direction of the spectral dispersion power of the prism is crossed with the grating. Thus, the prism separates the spectrum into individual orders while the grating produces a spectrum for each order. In this work, ZnS was selected as the material for the cross disperser, which was designed to cover the wavelength region, ${\lambda}=0.6-13{\mu}m$, with a spectral resolving power, $R{\geq}50$. A disperser was fabricated, and an evaluation of its surface was conducted. Two spectrometer designs, one adopting ZnS (${\lambda}=0.6-13{\mu}m$, $R{\geq}300$) and the other adopting CdZnTe (${\lambda}=1-23{\mu}m$, $R{\geq}250$), are presented. The spectrometers, each of which has no moving mechanical parts, consist simply of a disperser, a focusing mirror, and a detector.

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References

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