Julia Sheldakova

Hill-climbing algorithm for adaptive optical system with Shack-Hartmann sensor

We describe multi-dither adaptive optical system based on Shack-Hartmann wavefront sensor. RMS of the wavefront is minimized to get the best correction of the aberrated laser beam. Hill-climbing algorithm is used to determine voltages to be applied to the electrodes of a bimorph mirror which is used as a wavefront corrector.

The real-time atmospheric turbulence modeling and compensation with the use of adaptive optics

It is suggested to reconstruct the phase screens with the use of different deformable mirror types. In this work we present the results of the phase screen reproducing with the use of stacked-actuator deformable mirror and bimorph one. The reconstruction results were compared. The problems of the reconstruction were discussed.

Multi-dither adaptive optical system for laser beam shaping

We describe an adaptive optical closed loop system with bimorph mirror as a wavefront corrector and CCD camera at the focal plane of the lens as a sensor to obtain a good focal spot. Adaptive system can correct for the low-order aberrations with the frequency of corrected aberrations about 5 Hz. These parameters are mostly determined by the deformable mirror properties and multi-dither algorithm.

Atmopheric turbulence modeling by means of deformable mirrors with the use of phase interpolation

The efficiency of the reconstruction and correction of the real-time atmospheric turbulence by means of the stacked-actuator deformable mirror and the bimorph deformable mirror was shown. The characteristics of the spatial reconstruction are discussed. The phase screens interpolation methods are presented. The problems of the phase reconstruction are discussed.

New approaches of uniform focal spot formation by means of deformable mirror

In this paper the results of the flat-top beam formation by means of bimorph deformable mirror are presented. The problems of simulation are discussed. A new method for beam structure modification is suggested.

Wide aperture bimorph mirrors for high-power laser beam control

The deformable mirror with the size of 410×468 mm controlled by the bimorph piezoceramic plates and multilayer piezoceramic stacks was developed. The results of the measurements of the response functions of all the actuators and of the surface shape of the deformable mirror are presented in this paper. The study of the mirror with a Fizeau interferometer and a Shack-Hartmann wavefront sensor has shown that it was possible to improve the flatness of the surface down to a residual roughness of 0.033 μm (RMS). The possibility of correction of the aberrations in high power lasers was numerically demonstrated.

Uniform focal spot formation in adaptive system with Shack-Hartmann sensor and M2 sensor

Recent results of formation of uniform beam intensity distribution at the focal plane of a lens by means of bimorph deformable mirrors are presented. An approach based on the use of Shack-Hartmann wavefront sensor together with focal spot sensor (M2 meter) is suggested. Advantages and disadvantages are discussed.

A new method of the real-time atmospheric turbulence modeling

It is suggested to reconstruct the real-time atmospheric turbulence in the lab by means of the stacked-actuator deformable mirror and the bimorph deformable mirror. The characteristics of the spatial reconstruction are discussed. The phase screens interpolation methods are presented. The problems of the reconstruction are shown.

More than 500 mm deformable mirrors for high power laser beam correctio

Deformable mirrors with the size of 410×470 mm for high power lasers was developed. The results of the measurements of the response functions of all the actuators and of the surface shape of the deformable mirror are presented in this paper. The study of the mirror with a Fizeau interferometer and a Shack-Hartmann wavefront sensor has shown that it was possible to improve the flatness of the surface down to a residual roughness of 0.033 μm (RMS). The possibility of correction of the aberrations in high power lasers was numerically demonstrated.

Problems of uniform focal spot formation by means of deformable mirror

In this paper we present recent results of formation of different beam intensity distribution by means of bimorph deformable mirrors. We discuss the results of such formation as well as the problems that one faces on this way. A new method for beam structure modification is suggested based on the use of Shack-Hartmann wavefront sensor with the combination of standard M2 meter.