VPHG@INAF: efficient dispersing element in the UV-Vis spectral range

Abstract

Volume Phase Holographic Gratings (VPHGs) have proved to be of interest in astronomical fields because they show large diffraction efficiency and they can be tailored according to the spectrograph requirements. Different low dispersion VPHGs working in the UV-vis spectral region have been manufactured and fully characterized at INAF-Osservatorio Astronomico di Brera. Furthermore, such show a peak efficiency that reaches 90% and that remain large across the bandwidth. Dual order low dispersion VPHG has been developed covering the whole optical spectrum (from 350 nm to 1000 nm) in one exposure. The main features of these recent VPHGs are reported highlighting the efficiency performances.