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| Call for Papers>>Final Program |
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| Abstract of admission as follows: |
| Using the Finite-difference Time-domain Method Analyze Liquid Crystal on Silicon Polarization Grating |
| Quanbing Zhang
Sui Wei
Gongduan Zhang Anhui University |
| Abstract |
| A near field modeling of a high-resolution liquid crystal on silicon (LCOS) which is used as phase-only spatial light modulator for holographic display is deduced. The modeling method is based on the Finite-Difference Time-Domain (FDTD) method which is first proposed by Kane Yee in 1966 for normal incidence of light and isotropic media. Moreover, the Yee algorithm had two major hindrances - computationally intensive and large memory cost to its widespread use. Recently, the FDTD method’s hindrances have been overcome by the development of computer technologies. In this paper, based on the differential form of Maxwell’s equations in time domain, a leapfrog center differencing is used for electric and magnetic fields of periodic anisotropic instead isotropic media. By analyses the internal structure of LCOS, the material properties of polarization and birefringence are incorporated in the FDTD. To release normal incidence constraint, we apply a so called split-field update technique, proposed by Roden et al. which involves transforming and splitting the electric and magnetic fields in the phase domain to make their direction always normal to the problem structures to remove time gradients across the grid. Using a prototype holographic display system built by MD1280 (from three-five systems) as reflective phase-only spatial light modulator, the propagation of light in LCOS according to the vectorial nature of light is described. Then the optical activity and diffraction efficiency of LCOS as periodic grating at oblique incidence are analyzed using FDTD. The periodic boundary conditions at oblique incidence are implemented using the split-field update technique. Finally, in order to validate FDTD algorithm for LCOS, We have experimented with simulation data and real experimental data, and results prove that the FDTD simulation results is very consistent with the traditional Jones method analytical solutions and the real experimental data. Projects from National Natural Science Foundation of China:60872106 |
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