Bibcode
Sánchez Capuchino, J.; Hernández, E.; Reyes García-Talavera, M.; Montilla, I.; Simoes, R.; Tubío, O.
Referencia bibliográfica
Proceedings of the SPIE, Volume 10706, id. 1070604 13 pp. (2018).
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7
2018
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Descripción
This contribution is focused on the innovative aspects of the design of
the Laser Guide Star (LGS) Facility for the Gran Telescopio Canarias
(GTC) Adaptive Optics (GTCAO) System [6]. After a trade-off process
considering different alternatives, a preliminary opto-mechanical design
was defined, based on a "TOPTICA SodiumStar" laser to be launched
on-axis. To maximize throughput, different novelties around the optical,
and mechanical design of the Laser Launch System, including the Laser
Head, the Beam Transfer Optics and the Launch Telescope are emphasized
in this paper. In particular, all the elements of the Laser Launch
System have been compacted to be placed at the backside envelope of the
GTC M2 mechatronics. To fit in that envelope the thermal enclosure of
the Laser Head had to be redefined to avoid mechanical interferences and
science beam vignetting. An innovative closed-loop Laser Head cooling
approach was defined to be also arranged at the backside of GTC M2.
Performance simulations running in parallel to the on-axis LGS design
could not determine any difference in performance between the on-axis
and the off-axis launch. Hence, considering the higher packaging and
maintenance complexity required by the on-axis launch, GTC decided to
define the off-axis configuration as the new baseline approach. All the
solutions already defined for the on-axis approach that were applicable
to the new off-axis baseline were reused. To reduce the cost of future
upgrades, the LGS design allows generating and launching several LGS
with just one launch telescope splitting the light from the Laser Head.
In parallel with keeping the volume of the facility to a minimum, an
effort to keep its maintenance as simple as possible has been also made
to avoid the impact on the telescope operational costs.