Multi-functional two-dimensional holographic grating based on silver pattern coated by azopolymer.

• Periodically distributed refractive index and photoinduced birefringence. • Polarization modulation is realized with stable diffraction efficiency. • Different grating structures can be recorded in the same double-layer film. • The 2D diffraction device is angle-sensitive. A two-dimensional diffraction device with the properties of polarization modulation, angular sensitivity, polarization-independent diffraction efficiency and repeatable recording has been designed and fabricated in an azopolymer-silver double-layer film by means of two-step holographic exposure. A silver pattern is formed in the light field with the sinusoidally distributed intensity, and then a polarization holographic grating is recorded in the azobenzene liquid-crystalline layer through the interference of two orthogonally linearly polarized lasers. We report here that the polarization states of the diffraction beams from the recorded two-dimensional grating are orthogonally modulated; the diffraction efficiency is related to the incident angle of the probe light and the rotation angle between the two-step recording, while independent on the incident polarization state. Furthermore, the experimental results are analyzed through the scalar diffraction theory and Jones matrices. [ABSTRACT FROM AUTHOR]