In this paper, we propose a two-dimensional (2-D) triangular lattice photonic crystal plate by close-packed SiO2/ TiO2 layers with the stacking mode of ABABABA. By using the finite-difference time-domain (FDTD) method, negative refraction of a single Gaussian beam incident plate with different angles are respectively demonstrated; clear image spots of a point source with normalized frequency ω=0.3605(2πc/a) vertical incident media plate are obtained in the image plane. It can be found that the imaging properties are as same as the isotropic homogeneous medium with refractive index n=-1. The measurement results show that when the distance between the image and the upper surface of the sample V is 5.12a, 3.09a and 1.15a, the distance between the source and the lower surface of the sample U is a, 3a and 5a, respectively. This means that the sum of U and V is mostly equal to the thickness of the plate L and the negative effect of near-perfect lens is realized. This proposed structure with negative refraction properties may have great applications for the design of photonic crystal focusing devices.
A novel structure of photonic crystal coupled resonator optical waveguide (PC-CROW) with elliptical rod around
cavity is proposed to realize compact, high sensitivity modulated and high-performance buffering application. By
adjusting the long axis and short axis of the elliptical rods, the slow light and buffer performance of PC-CROW are
optimized. As ae=0.42a, be=0.20a, the group velocity is below 2.3053×10-4c, simultaneously, the buffer capacity C and delay time Ts reach the optimum value. Then the dynamic modulation of the slow light and buffer performance based on this optimized structure has been discussed systematically. The guided mode shifts linearly to short wavelength and delay time decreases exponentially as the external modulated voltage increases. And the modulation sensitivities are about 3.0nm/mV and 0.467ns/mV, respectively. These results show that the proposed structure has considerable potential for optical buffering application.
hese results show that the proposed structure has considerable potential for optical buffering application.