Tulip-form variable-curvature mirrors: interferometry and field compensation

Gerard R. Lemaitre; Silvio P. Mazzanti; Marc Ferrari

doi:10.1117/12.317099

24 July 1998 Tulip-form variable-curvature mirrors: interferometry and field compensation

Gerard R. Lemaitre, Silvio P. Mazzanti, Marc Ferrari

Proceedings Volume 3350, Astronomical Interferometry; (1998) https://doi.org/10.1117/12.317099
Event: Astronomical Telescopes and Instrumentation, 1998, Kona, HI, United States

Abstract

Active Optics methods are now capable to provide variable curvature mirrors (VCMs) having controlled sags in the focal range from f/∞to f/2.5. Those development have been carried out by the authors for the optical path equalizer dedicated to each Mersenne focus of the VLTI. The basic principle is to use VCMs as cat's eye mirrors in each delay line in order to achieve field compensations at the recombined Mersenne focii. During the VLTI development phase, cycloid form VCMs controlled by air pressure have been performed with a 10^-4 mirror sag resolution. The cycloid form has been selected for the VLTi delay lines. However, other analytical solutions from circular plates elasticity theory have been found. Two thickness distributions lead to tulip form VCMs controlled by a central force. One of them, using a lineic reaction at the edge is the object of this paper. Active optics design, construction features, test and experimental He-Ne interferograms obtained with 16mm boundary aperture and 10mm clear aperture are presented. The mean aspect-ratio of the tulip from VCM is d/t_0.5 approximately equals 60, providing a focal zoom range from f/∞ to f/2.5. The experiment is carried out form f/∞ to f/5.

Citation Download Citation

Gerard R. Lemaitre, Silvio P. Mazzanti, and Marc Ferrari "Tulip-form variable-curvature mirrors: interferometry and field compensation", Proc. SPIE 3350, Astronomical Interferometry, (24 July 1998); https://doi.org/10.1117/12.317099

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available