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Title: Demonstration of a 17 cm robust carbon fiber deformable mirror for adaptive optics

Abstract

Carbon-fiber reinforced polymer (CFRP) composite is an attractive material for fabrication of optics due to its high stiffness-to-weight ratio, robustness, zero coefficient of thermal expansion (CTE), and the ability to replicate multiple optics from the same mandrel. We use 8 and 17 cm prototype CFRP thin-shell deformable mirrors to show that residual CTE variation may be addressed with mounted actuators for a variety of mirror sizes. We present measurements of surface quality at a range of temperatures characteristic of mountaintop observatories. For the 8 cm piece, the figure error of the Al-coated reflective surface under best actuator correction is {approx}43 nm RMS. The 8 cm mirror has a low surface error internal to the outer ring of actuators (17 nm RMS at 20 C and 33 nm RMS at -5 C). Surface roughness is low (< 3 nm P-V) at a variety of temperatures. We present new figure quality measurements of the larger 17 cm mirror, showing that the intra-actuator figure error internal to the outer ring of actuators (38 nm RMS surface with one-third the actuator density of the 8 cm mirror) does not scale sharply with mirror diameter.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1026468
Report Number(s):
LLNL-PROC-499224
Journal ID: ISSN 0277-786X; TRN: US201120%%876
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Journal Volume: 8149; Conference: Presented at: SPIE Optics & Photonics, San Diego, CA, United States, Aug 21 - Aug 25, 2011
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; ACTUATORS; CARBON FIBERS; FABRICATION; MIRRORS; OPTICS; POLYMERS; ROUGHNESS; THERMAL EXPANSION

Citation Formats

Ammons, S M, Hart, M, Coughenour, B, Romeo, R, Martin, R, and Rademacher, M. Demonstration of a 17 cm robust carbon fiber deformable mirror for adaptive optics. United States: N. p., 2011. Web. doi:10.1117/12.894186.
Ammons, S M, Hart, M, Coughenour, B, Romeo, R, Martin, R, & Rademacher, M. Demonstration of a 17 cm robust carbon fiber deformable mirror for adaptive optics. United States. https://doi.org/10.1117/12.894186
Ammons, S M, Hart, M, Coughenour, B, Romeo, R, Martin, R, and Rademacher, M. 2011. "Demonstration of a 17 cm robust carbon fiber deformable mirror for adaptive optics". United States. https://doi.org/10.1117/12.894186. https://www.osti.gov/servlets/purl/1026468.
@article{osti_1026468,
title = {Demonstration of a 17 cm robust carbon fiber deformable mirror for adaptive optics},
author = {Ammons, S M and Hart, M and Coughenour, B and Romeo, R and Martin, R and Rademacher, M},
abstractNote = {Carbon-fiber reinforced polymer (CFRP) composite is an attractive material for fabrication of optics due to its high stiffness-to-weight ratio, robustness, zero coefficient of thermal expansion (CTE), and the ability to replicate multiple optics from the same mandrel. We use 8 and 17 cm prototype CFRP thin-shell deformable mirrors to show that residual CTE variation may be addressed with mounted actuators for a variety of mirror sizes. We present measurements of surface quality at a range of temperatures characteristic of mountaintop observatories. For the 8 cm piece, the figure error of the Al-coated reflective surface under best actuator correction is {approx}43 nm RMS. The 8 cm mirror has a low surface error internal to the outer ring of actuators (17 nm RMS at 20 C and 33 nm RMS at -5 C). Surface roughness is low (< 3 nm P-V) at a variety of temperatures. We present new figure quality measurements of the larger 17 cm mirror, showing that the intra-actuator figure error internal to the outer ring of actuators (38 nm RMS surface with one-third the actuator density of the 8 cm mirror) does not scale sharply with mirror diameter.},
doi = {10.1117/12.894186},
url = {https://www.osti.gov/biblio/1026468}, journal = {},
issn = {0277-786X},
number = ,
volume = 8149,
place = {United States},
year = {Mon Sep 12 00:00:00 EDT 2011},
month = {Mon Sep 12 00:00:00 EDT 2011}
}

Conference:
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