Design ad test of an adaptive optics system prototype for laser beam jitters reduction

This paper reports the experimental results that we have achieved from the tests of characterization of an Adaptive Optics (AO) Prototype implemented in our laboratory in compliance with the statements of the design previously carried out. Our purpose is to check the operation of the AO system that is expected to perform laser beam jitters reduction in the bandwidth of interest of interferometric Gravitational Wave (GW) antennas. Using the correspondence between Hermite Gauss polynomials and Zernike modes that alternatively represent the laser beam perturbations as demonstrated in our previous works, we have designed and implemented an AO system that extracts error signals in terms of Hermite Gauss coefficients and then corrects the wavefront through driver commands sent to the deformable mirror in terms of Zernike profiles. The results here reported confirm effectiveness and robustness of the Prototype which exhibits significant reduction of first and second order laser beam jitters. In particular we have measured the decrease of astigmatism and defocus modes of 60 dB at low frequency below 1 Hz and of 20 dB up to 200 Hz, which at the best of the present technology fulfils the requirements for noise reduction of the interferometric GW detectors.