Optimal Design of Hexagonal Multiphase Talbot Array Illuminator Based on PPLN

We theoretically and experimentally study a hexagonal multiphase Talbot array illuminator based on periodically poled LiNbO₃ crystal, in which phase shift is electro-optically tunable by controlling an external electric field. Numerical simulation revealed the effects on intensity distribution of diffraction field from array duty cycle, external electric field and diffraction distance. The higher light compression ratio can be obtained by adopting suitable duty cycle and diffraction distance under lower applied electric field. The highest light compression ratio can be realized by the optimal parameters, including array duty cycle of 71%, phase difference of 0.75π and diffraction position of 0.20 times Talbot distance. The experiment results correspond well with the simulation results.