Wave front sensing of an optical vortex and its correction in the close-loop adaptive system with bimorph mirror

Adaptive Optics and Optical Vortices

“…Next we consider the possibility to transform the wavefronts of the vortex beam by means of the closed-loop adaptive optical system with a wavefront sensor and a flexible deformable wavefront corrector. We can use the bimorph [166] as well as pusher-type [167,168] piezoceramic-based adaptive mirrors as a wavefront corrector. In the experiments a flexible bimorph mirror [166] and the Hartmann-Shack wavefront sensor with a new reconstruction algorithm [157][158][159] are employed.…”

“…We can use the bimorph [166] as well as pusher-type [167,168] piezoceramic-based adaptive mirrors as a wavefront corrector. In the experiments a flexible bimorph mirror [166] and the Hartmann-Shack wavefront sensor with a new reconstruction algorithm [157][158][159] are employed. An attempt is made to correct the laser beam carrying the optical vortex (namely, the Laguerre-Gaussian LG 0 1 mode), i.e., to remove its singularity.…”

“…In Figure 20 the wavefront corrector is situated in near rather than far field but at a relatively large distance from the spiral phase plate so that the proper vortex structure of the phase distribution is already formed in the wavefront corrector plane. The wavefront corrector (the bimorph adaptive mirror) 7 [166] is shown in Figure 21. It is composed of a substrate of LK-105 glass with reflecting coating and two foursquare piezoceramic plates, each measuring 45x45 mm and 0.4 mm thick.…”

Experimental detection of optical vortices with a Shack-Hartmann wavefront sensor

“…Two major difficulties in this field are the accurate and reliable detection of the vortices in the wavefront and the subsequent faithful reconstruction of the measured wavefront. Different reconstructors have been suggested [13,14] and some of these have been shown to work in laboratory conditions [15,16], while others work in theory but are impractical in reality [17,18].…”