Effect of counterpropagating beams on beam fanning in BaTiO3

Edge Enhancement, Contrast Reversal and Logic Operations Using Beam Fanning in a Photorefractive Iron-doped Barium Titanate Crystal

“…Attempts have been made to reduce the beam fanning effect in PR amplifiers, for example by rotating the crystal [13], using pulsed read-out [14], using adaptive filtering in the Fourier domain [15], employing achromatic gratings [16], exploiting the faster formation rate of signal gratings compared with the noise grating [17], using signal beam chopping [18], using time-modulated amplified wave-fronts, and employing spatial averaging over the random noise distribution [19] . Control over beam fanning in counter-propagation beam geometry in BaTiO 3 , has also been reported [20] .…”

Manifestation of coherence decay of optical vortices on scattering through photorefractive SBN crystal

“…In a sense, it is a nonlinear multi-two-wave mixing process [8,9]. In most of the applications related with PR materials this acts as a noise and several methods have been reported to overcome this noise caused by the beam fanning [12,13]. The dependence of beam fanning on the beam size and the sample thickness has also been studied [14,15].…”

“…Even though the beam fanning is responsible for depleting energy from the incident beam, it has some notable applications such as one beam recording [18], incoherent to coherent conversion [19] and double phase conjugation [20]. Looking at the different roles played by the beam fanning in applications of the PR materials [9][10][11][12][13][14][15][16][17][18][19][20], we intend to study its implications for beams with a helical wavefront which have started finding uses in PR materials as well [6][7][8].…”