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

Area of Science:

• Optical Engineering
• Astronomy
• Atmospheric Physics

Background:

• Testing adaptive optics (AO) systems requires realistic emulation of atmospheric turbulence.
• Existing methods for generating optical turbulence can be limited in reproducibility and achievable turbulence scales.

Purpose of the Study:

• To build and characterize an optical system emulating an 8m-class telescope.
• To investigate the statistical properties of novel etched glass phase-screens for turbulence generation.
• To assess the system's suitability for testing multiconjugate adaptive optics (MCAO).

Main Methods:

• Construction of an optical system incorporating rotating glass phase-screens.
• Characterization of phase-screens using direct imaging and Zernike coefficient variance analysis.
• Measurement of Fried parameter r0 at 0.633 microm.

Main Results:

• Phase-screens exhibit high transmissivity (85%) across 0.45-2.5 microm.
• Measured Fried parameter r0 values (0.43±0.04 and 0.81±0.03 microm) align with expectations within 10%.
• Screens demonstrate high reproducibility, enabling sub-millimetre r0 values.

Conclusions:

• The developed telescope emulator and phase-screens offer a powerful tool for atmospheric turbulence generation.
• This system facilitates systematic testing of various AO instrumentation.
• The reproducible nature of the screens overcomes previous limitations in achieving small r0 values.