Title
Athermal design of the optical tube assemblies for the ESO VLT four laser guidestar facility
Author
Henselmans, R.
Nijkerk, M.D.
Lemmen, M.H.J.
Rijnveld, N.
Kamphues, F.G.
Publication year
2011
Abstract
TNO is developing the Optical Tube Asssemblies (OTAs) for the ESO VLT Four Laser Guide Star Facility. The OTAs are Galilean 20x beam expanders, expanding a Ø15 mm input beam to a steerable Ø300 mm output beam with a wavefront quality requirement of 50 nm rms. The allowed defocus under the influence of the changing environmental air temperature (0-15°C, -0.7°C/hr gradient) is only 0.2 waves. The thermal behaviour of the system has been analyzed by combining optical, lumped mass and FE analyses. A design that is passively athermalized over a large temperature range as well as under the influence of thermal gradients has been developed. Extensive thermal testing has shown the system performs as required. This paper describes the design and test results. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).
Subject
Mechatronics, Mechanics & Materials
OM - Opto-Mechatronics
TS - Technical Sciences
Electronics
Athermal design
High-power laser
Optical Tube Assembly
OTA
Air temperature
Beam expanders
Defocus
Design and tests
FE analysis
Laser guide star
Lumped mass
Output beam
Temperature range
Thermal behaviours
Thermal testing
Wavefront quality
Optics
Design
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TNO identifier
442998
ISBN
9780819487599
ISSN
0277-786X
Source
Astronomical Adaptive Optics Systems and Applications IV, 21-24 August 2011, San Diego, CA, USA, 8149
Series
Proceedings of SPIE - The International Society for Optical Engineering
Article number
814905
Document type
conference paper