TY - JOUR
T1 - Mesospheric sodium layer variations with continuous laser modulation and effects on adaptive optics system
AU - Krishna, Sowmya Hassan
AU - Rey, Noelia Martinez
AU - Rigaut, Francois
AU - Roberts, Lyle E.
AU - D'Orgeville, Celine
N1 - Publisher Copyright:
© 2022 Society of Photo-Optical Instrumentation Engineers (SPIE).
PY - 2022/4/1
Y1 - 2022/4/1
N2 - The classical approaches for generating and studying a sodium guide star, direct imaging and light detection and ranging (LIDAR) technology are limited by the spatial resolution and equipment requirements. Therefore, the well-established technique to modulate continuous wave laser based on a pseudorandom binary sequence (PRBS) used in the field of radio detection and ranging and LIDAR has been extended to adaptive optics (AO). To monitor the sodium layer for applications such as AO and atmospheric studies, the technique was tested at the Calar Alto Observatory in 1999, Large Zenith Telescope in 2014, and by the University of Science and Technology of China in 2019. Based on these experiments, the PRBS modulation technique proved to be promising for the AO field. However, for this technique to be implemented in AO systems, it must be validated at different modulation strengths and modulation frequencies that satisfy the system requirements. Therefore, we aim to experimentally verify the PRBS modulation technique at a laser guide star facility installed at the 1.8 m Electro Optics Systems Telescope, Mount Stromlo, near Canberra, Australia. Numerical simulations are conducted with parameters at Mount Stromlo before the hardware implementation. The simulations show that the centroid error varies between 68 and 5 m for a low sodium column density. Additional numerical simulations are performed to verify the potential of the PRBS modulation technique to fulfill the laser guide star AO requirements of large telescopes. We show that with the implemented of PRBS modulation technique in one of the laser guide star (LGS) to monitor sodium layer can meet the LGS AO requirements of Giant Magellan Telescope even at low sodium column densities. Further, we discuss the computed results from the perspective of AO requirements, for the current and future implementation of the PRBS technique in the field of AO.
AB - The classical approaches for generating and studying a sodium guide star, direct imaging and light detection and ranging (LIDAR) technology are limited by the spatial resolution and equipment requirements. Therefore, the well-established technique to modulate continuous wave laser based on a pseudorandom binary sequence (PRBS) used in the field of radio detection and ranging and LIDAR has been extended to adaptive optics (AO). To monitor the sodium layer for applications such as AO and atmospheric studies, the technique was tested at the Calar Alto Observatory in 1999, Large Zenith Telescope in 2014, and by the University of Science and Technology of China in 2019. Based on these experiments, the PRBS modulation technique proved to be promising for the AO field. However, for this technique to be implemented in AO systems, it must be validated at different modulation strengths and modulation frequencies that satisfy the system requirements. Therefore, we aim to experimentally verify the PRBS modulation technique at a laser guide star facility installed at the 1.8 m Electro Optics Systems Telescope, Mount Stromlo, near Canberra, Australia. Numerical simulations are conducted with parameters at Mount Stromlo before the hardware implementation. The simulations show that the centroid error varies between 68 and 5 m for a low sodium column density. Additional numerical simulations are performed to verify the potential of the PRBS modulation technique to fulfill the laser guide star AO requirements of large telescopes. We show that with the implemented of PRBS modulation technique in one of the laser guide star (LGS) to monitor sodium layer can meet the LGS AO requirements of Giant Magellan Telescope even at low sodium column densities. Further, we discuss the computed results from the perspective of AO requirements, for the current and future implementation of the PRBS technique in the field of AO.
KW - light detection and ranging
KW - mesospheric sodium guide star
KW - pseudorandom binary sequence
KW - sodium laser guide star adaptive optics
UR - http://www.scopus.com/inward/record.url?scp=85133710053&partnerID=8YFLogxK
U2 - 10.1117/1.JATIS.8.2.029002
DO - 10.1117/1.JATIS.8.2.029002
M3 - Article
SN - 2329-4124
VL - 8
JO - Journal of Astronomical Telescopes, Instruments, and Systems
JF - Journal of Astronomical Telescopes, Instruments, and Systems
IS - 2
M1 - 029002
ER -