Volume phase holographic gratings for astronomy based on solid photopolymers

Zanutta, A.; Bianco, Andrea; Insausti, Maider; Garzón, F.
Bibliographical reference

Proceedings of the SPIE, Volume 9151, id. 91515X 15 pp. (2014).

Advertised on:
7
2014
Number of authors
4
IAC number of authors
2
Citations
4
Refereed citations
2
Description
Volume Phase Holographic Gratings (VPHG) are gaining more and more interest as optical dispersing elements in new astronomical spectrographs at low and medium resolution. A key point is the development of new photosensitive materials suitable to produce VPHGs that match the stringent requirements of the astronomical environment. Here we report on the performances of VPHG based on Bayfol®HX solid photopolymer films developed by Bayer MaterialScience AG. Parameters affecting the grating efficiency (e. g. photopolymer film thickness and refractive index modulation) are measured and linked to the performances of VPHG working in the VIS-NIR region. Moreover, the behavior at low temperature and the aging properties of such materials/gratings are reported. Substantial efficiency gains on a new VPHG installed at the Asiago's spectrograph are shown and proven on the observation of a standard star (hr5501).