TY - GEN
T1 - A support structure for a compliant deformable mirror
AU - Ernesto Penado, F.
AU - Clark, James H.
AU - Dugdale, Joel
PY - 2012
Y1 - 2012
N2 - The Navy's ground-based optical interferometer requires 10 discrete reflections for each of its six stations that transport stellar radiation into a six-way beam combiner where the modulated beams are overlapped in a collinear fashion and fringes obtained for analysis. Wavefront aberrations, introduced at each reflection from non-perfect mirrors, reduce the quality of fringe contrast and adversely affect the final science results. In practice, mirror fabrication and mounting methods generate small surface irregularities that produce aberrations in the reflected wavefront beam. Under multiple reflection scenarios, these errors do not necessarily cancel one another, and can increase the resultant wavefront distortion. In a previous paper, we showed a single-force actuator acting on the back surface of an 8-inch diameter Zerodur® mirror will achieve a canceling deformation in the reflective surface that substantially reduces the combined wavefront aberrations resulting from a 7-reflection beam. Our finite element model demonstrated that the peak-to-valley difference can be reduced from 210 nm to 55 nm. In this paper, we extend our previous work to include a support structure to contain the deforming mirror and analyze its interaction and effect on the corrected wavefront. Our design used the mechanical advantage gained from a tuned flexure plate with a simple motorized screw actuator applied to the back mirror surface to achieve an 87:1 deflection ratio on the front mirror surface. A practical design is proposed, the support structure and mirror analyzed using the finite element method, and the results presented and discussed.
AB - The Navy's ground-based optical interferometer requires 10 discrete reflections for each of its six stations that transport stellar radiation into a six-way beam combiner where the modulated beams are overlapped in a collinear fashion and fringes obtained for analysis. Wavefront aberrations, introduced at each reflection from non-perfect mirrors, reduce the quality of fringe contrast and adversely affect the final science results. In practice, mirror fabrication and mounting methods generate small surface irregularities that produce aberrations in the reflected wavefront beam. Under multiple reflection scenarios, these errors do not necessarily cancel one another, and can increase the resultant wavefront distortion. In a previous paper, we showed a single-force actuator acting on the back surface of an 8-inch diameter Zerodur® mirror will achieve a canceling deformation in the reflective surface that substantially reduces the combined wavefront aberrations resulting from a 7-reflection beam. Our finite element model demonstrated that the peak-to-valley difference can be reduced from 210 nm to 55 nm. In this paper, we extend our previous work to include a support structure to contain the deforming mirror and analyze its interaction and effect on the corrected wavefront. Our design used the mechanical advantage gained from a tuned flexure plate with a simple motorized screw actuator applied to the back mirror surface to achieve an 87:1 deflection ratio on the front mirror surface. A practical design is proposed, the support structure and mirror analyzed using the finite element method, and the results presented and discussed.
KW - Adaptive optics
KW - Finite element analysis
KW - Mirror deformations
KW - NPOI
KW - Optical interferometry
KW - Single force actuator
KW - Static deformable mirror
KW - Wavefront distortion
UR - http://www.scopus.com/inward/record.url?scp=84872556862&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84872556862&partnerID=8YFLogxK
U2 - 10.1117/12.930008
DO - 10.1117/12.930008
M3 - Conference contribution
AN - SCOPUS:84872556862
SN - 9780819492081
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Optical System Alignment, Tolerancing, and Verification VI
T2 - Optical System Alignment, Tolerancing, and Verification VI
Y2 - 12 August 2012 through 13 August 2012
ER -