In situ holograms and two-wave mixing amplification of conical diffraction vector waves

Holographic recording and selective reconstruction and amplification of conical diffraction vector waves are demonstrated using a nonlinear photorefractive Sn2P2S6 crystal acting simultaneously as the medium producing the conical diffraction effect and as holographic storage material. It is shown that upon propagation of the object wave along one of the optical axes of the biaxial crystal, the azimuthal spreading of the local linear polarizations across the conical diffraction ring allows its holographic recording with any combinations of the object and reference waves' input polarizations, including mutually orthogonal ones. We discuss the dependence of the recording and read-out polarizations on the recovered and amplified patterns and provide a simplified model qualitatively accounting for all the main observed features. The approach permits a tailoring of the reconstructed or amplified vector waves in terms of intensity and polarization distributions and opens interesting perspectives for their static or dynamic manipulation. (c) 2024 Optica Publishing Group