The Blue Multi Unit Spectroscopic Explorer (BlueMUSE) on the VLT: characterization of two VPHG prototypes based on dichromated gelatin and photopolymer recording materials
| Autor: | Jeanneau, Alexandre, Bianco, Andrea, Clawson, Andrew, Frangiamore, Michele, Pearson, Elroy, Pinard, Laurent, Schmoll, Jürgen, Richard, Johan, Giroud, Rémi, Laurent, Florence, Bacon, Roland |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | Volume-phase holographic gratings (VPHGs) are widely used in astronomical spectrographs due to their adaptability and high diffraction efficiency. Most VPHGs in operation use dichromated gelatin as a recording material, whose performance is sensitive to the coating and development process, especially in the near-UV. In this letter, we present the characterization of two UV-blue VPHG prototypes for the BlueMUSE integral field spectrograph on the VLT, based on dichromated gelatin and the Bayfol$\circledR$HX photopolymer film as recording materials. Our measurements show that both prototypes meet the required diffraction efficiency and exhibit similar performance with a wavelength-average exceeding 70% in the 350-580 nm range. Deviations from theoretical models increase towards 350 nm, consistently with previous studies on similar gratings. We also report similar performances in terms spatial uniformity and grating-to-grating consistency. Likewise, no significant differences in wavefront error or scattered light are observed between the prototypes. Comment: 7 pages, 5 figures, 1 table. Presented at SPIE "Astronomical Telescopes and Instrumentation", June 2024, in Yokohama, as part of "Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation VI" |
| Databáze: | arXiv |
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