Adaptive conversion of a wavefront-distortion beam to near-diffraction-limited flattop beam based on stochastic parallel gradient descent algorithm

In this paper, a system of containing dual deformable mirrors (DMs) is proposed to adaptively conversion of input beam with wave front distortion into near-diffraction-limited flattop beam based on the stochastic parallel gradient descent (SPGD) algorithm. In the analysis, the wave front distortion of the input beam is chosen as the Zernike representation of Kolmogoroff spectrum of turbulence. The whole shaping system is controlled by the SPGD algorithm. One DM adaptively redistributes the intensity of the input beam and the other adaptively compensates the wave front of the output beam. The near-diffraction-limited flattop beams with different parameters are realized by this technique. The near-diffraction-limited square flattop beam retains an flattop intensity distribution without significant diffraction peaks for a working distance of more than 60cm in the near field.

[1]  C. M. Jefferson,et al.  Design and performance of a refractive optical system that converts a Gaussian to a flattop beam. , 2000, Applied optics.

[2]  Daniel J Heinzen,et al.  1.5% root-mean-square flat-intensity laser beam formed using a binary-amplitude spatial light modulator. , 2009, Applied optics.

[3]  R. Noll.  Zernike polynomials and atmospheric turbulence , 1976 .

[4]  C. J. Kastner,et al.  Beam profile shaping for laser radars that use detector arrays. , 1982, Applied optics.

[5]  Louis A. Romero,et al.  Lossless laser beam shaping , 1996 .

[6]  J. Hunt,et al.  Suppression of self-focusing through low-pass spatial filtering and relay imaging. , 1978, Applied optics.

[7]  H M Haskal.  Laser recording with truncated Gaussian beams. , 1979, Applied optics.

[8]  K. Witte,et al.  Correction of strong phase and amplitude modulations by two deformable mirrors in a multistaged Ti:sapphire laser. , 2002, Optics letters.

[9]  Mikhail A. Vorontsov,et al.  Stochastic parallel-gradient-descent technique for high-resolution wave-front phase-distortion correction , 1998 .

[10]  Pu Zhou,et al.  Coherent beam combination of three two-tone fiber amplifiers using stochastic parallel gradient descent algorithm. , 2009, Optics letters.

[11]  R El-Agmy,et al.  Adaptive beam profile control using a simulated annealing algorithm. , 2005, Optics express.

[12]  C. Michel,et al.  Generation of a flat-top laser beam for gravitational wave detectors by means of a nonspherical Fabry-Perot resonator. , 2007, Applied optics.

[13]  Hulya Kirkici,et al.  Optical beam-shaping design based on aspherical lenses for circularization, collimation, and expansion of elliptical laser beams. , 2008, Applied optics.

[14]  Fred M. Dickey,et al.  Laser beam shaping applications , 2005 .