Shaping of ultrashort pulsed beams with volume holographic gratings recorded in anisotropic crystals

A new technique for ultrashort pulsed beams (UPBs) shaping that uses volume holographic gratings (VHGs) recorded in anisotropic crystals by modulating the polarization states of the input UPBs is proposed and analyzed. Our approach is based on the investigation that when a VHG recorded in anisotropic crystals is illuminated by a UPB, the spectral and temporal widths and the shapes of the diffracted and transmitted pulsed beams vary with the polarization state of the input UPB, based on the extended coupled wave theory of Kogelnik which combines with the dispersion effect of the crystal materials. By using this approach, the modulation ranges of the spectral and temporal widths of the output UPB can be controlled by the parameters of the grating. Moreover, the diffraction efficiency of the volume holographic grating is analyzed, which also varies with the polarization state of the input UPB. An example of using this approach is given that a linearly polarized Gaussian-shaped UPB with duration of 30fs is effectively shaped with a transmission volume holographic grating recorded in photorefractive LiNbO3 crystals.