TY - GEN
T1 - Ultrafast laser micro-stressing for correction of thin fused silica optics for the Lynx X-Ray Telescope Mission
AU - Zuo, Heng E.
AU - Chalifoux, Brandon D.
AU - Heilmann, Ralf K.
AU - Schattenburg, Mark L.
N1 - Publisher Copyright:
© 2018 SPIE.
PY - 2018
Y1 - 2018
N2 - Fused silica exhibits high nonlinear optical response when exposed to ultrashort laser pulses, and the rapid development of femtosecond laser technology since the 1990s has greatly advanced the processing of such transparent materials. Since then, ultrafast laser micromachining has been widely implemented to remove materials or change material properties, from surface ablation to waveguide fabrication. Recently, we devised a potential use of this technique for optics precision correction of future space telescopes, for example the Lynx X-ray telescope mission. This novel mirror figure correction process provides a rapid and precise way of creating local micro deformation within the interior of thin mirrors, which then induces macro structural changes in surface figure to meet the stringent angular resolution requirements for the X-ray telescope. The method is highly controllable and deterministic, and the long-term stability of the laser-induced material changes makes it promising for future space telescope missions. In this paper, we review the mechanisms and nonlinear optical phenomena of femtosecond laser interaction with fused silica. We also report on the current development of our laser pulses generation, focusing, imaging and an in-situ wavefront sensing systems, as well as our procedure for measuring and correcting mirror substrates. Preliminary experimental results of local deformation and stress changes in flat thin fused silica mirror substrates are shown, demonstrating the correctability of fused silica substrates within a capture range of 1 μm in surface peak-to-valley or 200 in RMS slope using local laser micromachining. We also showed the laser induced integrated stress increases linearly with the micromachining density.
AB - Fused silica exhibits high nonlinear optical response when exposed to ultrashort laser pulses, and the rapid development of femtosecond laser technology since the 1990s has greatly advanced the processing of such transparent materials. Since then, ultrafast laser micromachining has been widely implemented to remove materials or change material properties, from surface ablation to waveguide fabrication. Recently, we devised a potential use of this technique for optics precision correction of future space telescopes, for example the Lynx X-ray telescope mission. This novel mirror figure correction process provides a rapid and precise way of creating local micro deformation within the interior of thin mirrors, which then induces macro structural changes in surface figure to meet the stringent angular resolution requirements for the X-ray telescope. The method is highly controllable and deterministic, and the long-term stability of the laser-induced material changes makes it promising for future space telescope missions. In this paper, we review the mechanisms and nonlinear optical phenomena of femtosecond laser interaction with fused silica. We also report on the current development of our laser pulses generation, focusing, imaging and an in-situ wavefront sensing systems, as well as our procedure for measuring and correcting mirror substrates. Preliminary experimental results of local deformation and stress changes in flat thin fused silica mirror substrates are shown, demonstrating the correctability of fused silica substrates within a capture range of 1 μm in surface peak-to-valley or 200 in RMS slope using local laser micromachining. We also showed the laser induced integrated stress increases linearly with the micromachining density.
KW - Lynx
KW - X-ray telescope
KW - figure correction
KW - fused silica
KW - micro-stressing
KW - thin optics
KW - ultrafast laser
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UR - http://www.scopus.com/inward/citedby.url?scp=85051859508&partnerID=8YFLogxK
U2 - 10.1117/12.2314961
DO - 10.1117/12.2314961
M3 - Conference contribution
AN - SCOPUS:85051859508
SN - 9781510619517
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Space Telescopes and Instrumentation 2018
A2 - Nikzad, Shouleh
A2 - Den Herder, Jan-Willem A.
A2 - Nakazawa, Kazuhiro
PB - SPIE
T2 - Space Telescopes and Instrumentation 2018: Ultraviolet to Gamma Ray
Y2 - 10 June 2018 through 15 June 2018
ER -