Beam fanning is a process similar to two-beam coupling, except in this case, only one beam is incident on the material, and its energy is transferred into scattered light. As a result of the energy transfer, scattered light is amplified, and a "fan" is observed. Since energy transfer direction can be changed by switching the polarity of the applied electric field, beam fanning effect can be maximized or minimized depending on the polarity.A. Grunnet-Jepsen et al., J. Opt. Soc. Am. 15, 901 (1998)

Beam fanning effect can be used in continuous wave optical limiting applications that require optical transparency at low powers, while limiting the trasmitted power at high powers. In this case, polarity of the applied electric field that maximizes beam fanning effect should be used, so that the power of the light beam transmitted through the photorefractve material is reduced.U. Gubler et al., Adv. Mat. 14, 313 (2002), O. Ostroverkhova et al., Adv. Funct. Mat. 12, 621 (2002)

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