TY - GEN
T1 - Higher dispersion and efficiency Bragg gratings for optical spectroscopy
AU - Saunders, Will
AU - Zhang, Kai
AU - Flügel-Paul, Thomas
PY - 2018/7/10
Y1 - 2018/7/10
N2 - Massively multiplexed spectroscopic stellar surveys such as MSE present enormous challenges in the spectrograph design. The combination of high multiplex, large telescope aperture, high resolution (R∼40,000) and natural seeing implies that multiple spectrographs with large beam sizes, large grating angles, and fast camera speeds are required, with high cost and risk. An attractive option to reduce the beam size is to use Bragg-type gratings at much higher angles than hitherto considered. As well as reducing the spectrograph size and cost, this also allows the possibility of very high efficiency due to a close match of s and p-polarization Bragg efficiency peaks. The grating itself could be a VPH grating, but Surface Relief (SR) gratings offer an increasingly attractive alternative, with higher maximum line density and better bandwidth. In either case, the grating needs to be immersed within large prisms to get the light to and from the grating at the required angles. We present grating designs and nominal spectrograph designs showing the efficiency gains and size reductions such gratings might allow for the MSE high resolution spectrograph.
AB - Massively multiplexed spectroscopic stellar surveys such as MSE present enormous challenges in the spectrograph design. The combination of high multiplex, large telescope aperture, high resolution (R∼40,000) and natural seeing implies that multiple spectrographs with large beam sizes, large grating angles, and fast camera speeds are required, with high cost and risk. An attractive option to reduce the beam size is to use Bragg-type gratings at much higher angles than hitherto considered. As well as reducing the spectrograph size and cost, this also allows the possibility of very high efficiency due to a close match of s and p-polarization Bragg efficiency peaks. The grating itself could be a VPH grating, but Surface Relief (SR) gratings offer an increasingly attractive alternative, with higher maximum line density and better bandwidth. In either case, the grating needs to be immersed within large prisms to get the light to and from the grating at the required angles. We present grating designs and nominal spectrograph designs showing the efficiency gains and size reductions such gratings might allow for the MSE high resolution spectrograph.
KW - High resolution spectroscopy
KW - MSE
KW - Multiobject spectroscopy
KW - Stellar spectroscopy
KW - Surface relief gratings
KW - VPH gratings
UR - http://www.scopus.com/inward/record.url?scp=85053478457&partnerID=8YFLogxK
U2 - 10.1117/12.2313958
DO - 10.1117/12.2313958
M3 - Conference proceeding contribution
AN - SCOPUS:85053478457
SN - 9781510619654
T3 - Proceedings of SPIE
SP - 1
EP - 10
BT - Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III
A2 - Navarro, Ramón
A2 - Geyl, Roland
PB - SPIE
CY - Bellingham, Washington
T2 - Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III 2018
Y2 - 10 June 2018 through 15 June 2018
ER -