Design and testing of a dynamic refocus system for Rayleigh laser beacons

James A. Georges, Proteep Mallik, Thomas Stalcup, J Roger P Angel, Roland Sarlot

Research output: Chapter in Book/Report/Conference proceedingConference contribution

18 Citations (Scopus)

Abstract

We present the design, laboratory tests and preliminary field tests of a dynamic refocus system for 351nm Rayleigh beacon laser guide stars. The purpose of dynamic refocus is to increase the beacon signal from a pulsed laser, by maintaining focus in a fixed plane while the laser pulse travels through the atmosphere over an extended height range. The focusing element in our system is a moving concave mirror. The optics have been designed and built to focus on a ring of 5 beacons at 1 arc minute radius at the 6.5 m MMT, covering the range 18-40 km. Laboratory tests of image quality resulted in 0.5 arcsec refocused images corresponding to the height range 22 - 28 km, free from spherical aberration. Preliminary field tests were performed on the Mt. Bigelow Observatory 1.5 m telescope, with a frequency-tripled, Q-switched YLF laser beam projected from a 25 cm telescope. To simulate an off-axis sub-aperture of the MMT, the laser and telescope axes were set 3 m apart and reimaging optics were placed ahead of the refocus unit to image at the same plate scale as the MMT (500 μm/arcsec). Returns from different heights were selected by gating the detector with a Pockels cell. Returns over a 10 km height range from 8km to 18km were brought into focus for a total mirror motion measured to be 900 μm. The system is now ready for testing dynamic refocus, which will be accomplished by attaching the mirror to a metal resonator tuned to the laser pulse frequency. The range from 23 to 35 km to be used will require a motion of 500 μm.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsP.L. Wizinowich, D. Bonaccini
Pages473-483
Number of pages11
Volume4839
Edition1
DOIs
StatePublished - 2002
EventAdaptive Optical System Technologies II - Waikoloa, HI, United States
Duration: Aug 22 2002Aug 26 2002

Other

OtherAdaptive Optical System Technologies II
CountryUnited States
CityWaikoloa, HI
Period8/22/028/26/02

Fingerprint

beacons
Telescopes
Dynamical systems
Mirrors
Lasers
Laser pulses
Optics
field tests
Testing
telescopes
mirrors
YLF lasers
lasers
Observatories
optics
Aberrations
Pulsed lasers
laser guide stars
Image quality
Stars

Keywords

  • Dynamic refocus
  • Laser guide stars
  • Multi-conjugate adaptive optics
  • Raleigh beacons

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this

Georges, J. A., Mallik, P., Stalcup, T., Angel, J. R. P., & Sarlot, R. (2002). Design and testing of a dynamic refocus system for Rayleigh laser beacons. In P. L. Wizinowich, & D. Bonaccini (Eds.), Proceedings of SPIE - The International Society for Optical Engineering (1 ed., Vol. 4839, pp. 473-483) https://doi.org/10.1117/12.459354

Design and testing of a dynamic refocus system for Rayleigh laser beacons. / Georges, James A.; Mallik, Proteep; Stalcup, Thomas; Angel, J Roger P; Sarlot, Roland.

Proceedings of SPIE - The International Society for Optical Engineering. ed. / P.L. Wizinowich; D. Bonaccini. Vol. 4839 1. ed. 2002. p. 473-483.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Georges, JA, Mallik, P, Stalcup, T, Angel, JRP & Sarlot, R 2002, Design and testing of a dynamic refocus system for Rayleigh laser beacons. in PL Wizinowich & D Bonaccini (eds), Proceedings of SPIE - The International Society for Optical Engineering. 1 edn, vol. 4839, pp. 473-483, Adaptive Optical System Technologies II, Waikoloa, HI, United States, 8/22/02. https://doi.org/10.1117/12.459354
Georges JA, Mallik P, Stalcup T, Angel JRP, Sarlot R. Design and testing of a dynamic refocus system for Rayleigh laser beacons. In Wizinowich PL, Bonaccini D, editors, Proceedings of SPIE - The International Society for Optical Engineering. 1 ed. Vol. 4839. 2002. p. 473-483 https://doi.org/10.1117/12.459354
Georges, James A. ; Mallik, Proteep ; Stalcup, Thomas ; Angel, J Roger P ; Sarlot, Roland. / Design and testing of a dynamic refocus system for Rayleigh laser beacons. Proceedings of SPIE - The International Society for Optical Engineering. editor / P.L. Wizinowich ; D. Bonaccini. Vol. 4839 1. ed. 2002. pp. 473-483
@inproceedings{a5d792056d464d42812b3338f874db5f,
title = "Design and testing of a dynamic refocus system for Rayleigh laser beacons",
abstract = "We present the design, laboratory tests and preliminary field tests of a dynamic refocus system for 351nm Rayleigh beacon laser guide stars. The purpose of dynamic refocus is to increase the beacon signal from a pulsed laser, by maintaining focus in a fixed plane while the laser pulse travels through the atmosphere over an extended height range. The focusing element in our system is a moving concave mirror. The optics have been designed and built to focus on a ring of 5 beacons at 1 arc minute radius at the 6.5 m MMT, covering the range 18-40 km. Laboratory tests of image quality resulted in 0.5 arcsec refocused images corresponding to the height range 22 - 28 km, free from spherical aberration. Preliminary field tests were performed on the Mt. Bigelow Observatory 1.5 m telescope, with a frequency-tripled, Q-switched YLF laser beam projected from a 25 cm telescope. To simulate an off-axis sub-aperture of the MMT, the laser and telescope axes were set 3 m apart and reimaging optics were placed ahead of the refocus unit to image at the same plate scale as the MMT (500 μm/arcsec). Returns from different heights were selected by gating the detector with a Pockels cell. Returns over a 10 km height range from 8km to 18km were brought into focus for a total mirror motion measured to be 900 μm. The system is now ready for testing dynamic refocus, which will be accomplished by attaching the mirror to a metal resonator tuned to the laser pulse frequency. The range from 23 to 35 km to be used will require a motion of 500 μm.",
keywords = "Dynamic refocus, Laser guide stars, Multi-conjugate adaptive optics, Raleigh beacons",
author = "Georges, {James A.} and Proteep Mallik and Thomas Stalcup and Angel, {J Roger P} and Roland Sarlot",
year = "2002",
doi = "10.1117/12.459354",
language = "English (US)",
volume = "4839",
pages = "473--483",
editor = "P.L. Wizinowich and D. Bonaccini",
booktitle = "Proceedings of SPIE - The International Society for Optical Engineering",
edition = "1",

}

TY - GEN

T1 - Design and testing of a dynamic refocus system for Rayleigh laser beacons

AU - Georges, James A.

AU - Mallik, Proteep

AU - Stalcup, Thomas

AU - Angel, J Roger P

AU - Sarlot, Roland

PY - 2002

Y1 - 2002

N2 - We present the design, laboratory tests and preliminary field tests of a dynamic refocus system for 351nm Rayleigh beacon laser guide stars. The purpose of dynamic refocus is to increase the beacon signal from a pulsed laser, by maintaining focus in a fixed plane while the laser pulse travels through the atmosphere over an extended height range. The focusing element in our system is a moving concave mirror. The optics have been designed and built to focus on a ring of 5 beacons at 1 arc minute radius at the 6.5 m MMT, covering the range 18-40 km. Laboratory tests of image quality resulted in 0.5 arcsec refocused images corresponding to the height range 22 - 28 km, free from spherical aberration. Preliminary field tests were performed on the Mt. Bigelow Observatory 1.5 m telescope, with a frequency-tripled, Q-switched YLF laser beam projected from a 25 cm telescope. To simulate an off-axis sub-aperture of the MMT, the laser and telescope axes were set 3 m apart and reimaging optics were placed ahead of the refocus unit to image at the same plate scale as the MMT (500 μm/arcsec). Returns from different heights were selected by gating the detector with a Pockels cell. Returns over a 10 km height range from 8km to 18km were brought into focus for a total mirror motion measured to be 900 μm. The system is now ready for testing dynamic refocus, which will be accomplished by attaching the mirror to a metal resonator tuned to the laser pulse frequency. The range from 23 to 35 km to be used will require a motion of 500 μm.

AB - We present the design, laboratory tests and preliminary field tests of a dynamic refocus system for 351nm Rayleigh beacon laser guide stars. The purpose of dynamic refocus is to increase the beacon signal from a pulsed laser, by maintaining focus in a fixed plane while the laser pulse travels through the atmosphere over an extended height range. The focusing element in our system is a moving concave mirror. The optics have been designed and built to focus on a ring of 5 beacons at 1 arc minute radius at the 6.5 m MMT, covering the range 18-40 km. Laboratory tests of image quality resulted in 0.5 arcsec refocused images corresponding to the height range 22 - 28 km, free from spherical aberration. Preliminary field tests were performed on the Mt. Bigelow Observatory 1.5 m telescope, with a frequency-tripled, Q-switched YLF laser beam projected from a 25 cm telescope. To simulate an off-axis sub-aperture of the MMT, the laser and telescope axes were set 3 m apart and reimaging optics were placed ahead of the refocus unit to image at the same plate scale as the MMT (500 μm/arcsec). Returns from different heights were selected by gating the detector with a Pockels cell. Returns over a 10 km height range from 8km to 18km were brought into focus for a total mirror motion measured to be 900 μm. The system is now ready for testing dynamic refocus, which will be accomplished by attaching the mirror to a metal resonator tuned to the laser pulse frequency. The range from 23 to 35 km to be used will require a motion of 500 μm.

KW - Dynamic refocus

KW - Laser guide stars

KW - Multi-conjugate adaptive optics

KW - Raleigh beacons

UR - http://www.scopus.com/inward/record.url?scp=0038398990&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0038398990&partnerID=8YFLogxK

U2 - 10.1117/12.459354

DO - 10.1117/12.459354

M3 - Conference contribution

AN - SCOPUS:0038398990

VL - 4839

SP - 473

EP - 483

BT - Proceedings of SPIE - The International Society for Optical Engineering

A2 - Wizinowich, P.L.

A2 - Bonaccini, D.

ER -