Compensation for distortions of a telescope's primary mirror by means of a volume dynamic hologram

Abstract

We describe a number of experiments devoted to compensation for aberrations in the primary mirror of a telescope using a volume dynamic holography technique, where the writing and reading of the hologram are carried out indepeadently.Three sets of experiments demonstrating holographic aberration correction have been performed. In all cases transmitting holograms were formed in photorefractive crystals such as BSO and SBN. In experiments with a small diameter primary minor the image is formed by a multicolor point-like object. The system includes an unit wich compensates for the hologram dispersion. The aberration correction of a six-segmented primary mirror of 1 50 mm in diameter is demonstrated in conditions where there is a pronounced difference in the wavelengths of the recording beams and that of the source observed (AX=O.12 tim). The experiments on observation an extended object of continuous spectrum (&=O.35 tm) with a single primary mirror of 1 50 mm diameter have been also made.All these experiments indicate an efficient compensation for distortions ofthe primary mirror by the hologram.

Real-time holographic correction of image of a moving object observed by a telescope with a membrane primary mirror

“…The beam reflected by the beamsplitter reads out the information about distortions of the membrane-type primary mirror 12. Then it is focused by lens 13 into point C and, when diverging from this point, it is successively reflected by mirrors 16, 12,16, and 15 and is focused at point C. After objective 8, the collimated beam enters nonlinear medium 11 at the needed angle with respect to the reference beam. Shaping of the beam from the object of observation is shown in Fig.…”

“…The prototype of the telescope, we designed and studied, has already been repeatedly described in the literature [8][9][10][11][12] . Figure 1 shows schematic of the main part of the demonstration desktop prototype of the telescope with the image distortion compensation.…”