光子晶体中紫外波段的异常透射

Extraordinary Transmission in Ultraviolet Wavebands in Photonic Crystals

采用时域有限差分法(FDTD)对三种不同材料(金属Al、半导体Ga_(2)O_(3)和绝缘体SiO_(2))的矩型结构光子晶体进行了模拟计算,研究空气柱孔径变化对光子晶体光学传输特性及带隙宽度的影响。数值计算结果表明,晶格常数不变,空气柱孔径增大时,三种材料光子晶体在紫外光区及可见光区的透过率增大,反射率减小。Al光子晶体的孔径增大时,可见光区禁带宽度减小;Ga_(2)O_(3)光子晶体孔径增大时,禁带宽度增大;SiO2的TE模和TM模光子禁带较宽,孔径增大,禁带宽度亦增大。三种材料光子晶体带隙的波长范围几乎都处于可见光波段,进入紫外光波段的波长范围很短。

The finite-difference time-domain method(FDTD)is used to simulate the photonic crystal structures made of three different materials(metal Al,semiconductor Gaz Os,and insulator SiO,).The size effect on optical transmission properties and bandgap width of the photonic crystals from air column aperture is studied in detail.Numerical results show an increase in transmittance and a decrease in reflectivity in the ultraviolet and visible light regions for all three materials with increasing the size of air column aperture if the lattice constant is kept a constant.When the aperture size of Al photonic crystals increases,the bandgap width in visible light region decreases;For Gaz O3 photonic crystals,the band gap increases when the aperture size increases;The TE and TM mode photonic band gaps are wider in SiO2,and the band gap width increases with increasing the aperture size.The wavelength range of photonic crystal bandgap for all three materials mostly locates in the visible light range with a little ultraviolet band.