Refractive Index of ZnSe at Cryogenic Temperatures†

This report describes an extensive data set on the refractive index of ZnSe that provides full high resolution coverage of the CRIRES operating range in both wavelength and temperature. By combining our prototype instrument model of CRIRES with these data our project to provide wavelength calibration for IR Echelle spectrographs (WIRE) has reached an important milestone and is ready to support the laboratory test phase of CRIRES. The data have been taken at the CHARMS facility at Goddard Space Flight Center and are available to us by a special agreement between ECF’s Instrument Physical Modeling Group (IPMG) and CHARMS/NASA. Analysis of the ZnSe data provides additional insight into the expected properties of CRIRES and indicates how one can optimise instrument operations. This report also demonstrates the use of such data within the optical model (Bristow et al. 2005) and illustrates how the model and its predictive power can be tested and validated using dedicated test measurements to be obtained from ESO’s integration laboratory. † The data on the refractive index of ZnSe described in this report were measured by D. Leviton and B. Frey at CHARMS (NASA/Goddard SFC). ST-ECF Instrument Science Report WIRE – 2005 – 003