Polarization holographic gratings in an azobenzene copolymer with linear and circular photoinduced birefringence

Polarization holographic recordings in an azobenzene copolymer were performed by using the interference of two linearly orthogonally polarized beams. The first order diffraction efficiency of the recorded gratings was modulated by the polarization direction of the probe beam as a consequence of the spatial modulation of the linear and circular photoinduced birefringence. The polarization of the diffractive wave was also strongly dependent on the polarization of the readout wave. The value of the photoinduced linear and circular birefringence was evaluated through Jones matrix calculations, and the obtained values were experimentally confirmed to be valid by single beam excitation measurements.