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Atmosphere-like turbulence generation with surface-etched phase-screens

Stefan Hippler·Felix Hormuth·David J. Butler·Wolfgang Brandner·Thomas Henning
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Abstract

We built and characterized an optical system that emulates the optical characteristics of an 8m-class telescope like the Very Large Telescope. The system contains rotating glass phase-screens to generate realistic atmosphere-like optical turbulence, as needed for testing multi-conjugate adaptive optics systems. In this paper we present an investigation of the statistical properties of two phase-screens etched on glass-plate surfaces, obtained from Silios Technologies. Those etched screens are highly transmissive (above 85%) from 0.45 to 2.5 microns. From direct imaging, their Fried parameter r0 values (0.43+-0.04 mm and 0.81+-0.03 mm, respectively, at 0.633 microns) agree with the expectation to within 10%. This is also confirmed by a comparison of measured and expected Zernike coefficient variances. Overall, we find that those screens are quite reproducible, allowing sub-millimetre r0 values, which were difficult to achieve in the past. We conclude that the telescope emulator and phase-screens form a powerful atmospheric turbulence generator allowing systematic testing of different kinds of AO instrumentation.

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Stefan Hippler, Felix Hormuth, David J. Butler, Wolfgang Brandner, Thomas Henning. 2006-09-15. Atmosphere-like turbulence generation with surface-etched phase-screens. https://doi.org/10.1364/oe.14.010139

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