Study On Diffractive Properties Of Liquid Crystal Voltage Controllable Phase Grating

In this dissertation, a research has been made on the Liquid crystal diffractive grating .Because of its diffractive property is tunable by the voltage applied ,and also with its compact structure, handiness and without mechanism,etc,the LC diffractive grating has wildly potential use in space communication, tunable filter,optical cross interconnection and the back display,etc. So, a lot of reseachers have made wildly study on it, including diffrative efficiency, fringing field effect, various structures and its applications.There are three parts included in this dissertation.Firstly, the difference iterative method is used to simulate the one demension and two demension LC director distribution,and then the fringe field effect is analysised based on the director distribution.At the same time ,the scale diffractive theroy is used to analysis the diffractive efficiency under the different pitches and fixed voltages applied on it.Then we conclude that the fringe field effcet destroys the ability of the phase modulation badly.So the diffractive effociency is also affected severely.In the second part, the Finite-Difference Time-Domain (FDTD) method is successfully used to analysis diffractive efficiencys under the different voltages applied to the element.It is denoted that the FDTD method is feasible to analysis the LC grating's diffrative properties.In the third part, a novel technology, wavefront recurrence algorithm, is proposed here to reduce the computational time in the LC cascade structure. And the the results to analysis the cascade structure is given to testify its validity.