Grating-induced omnidirectional refraction of self-collimated beams at a photonic crystal surface

Abstract

We report that self-collimated beams from a photonic crystal can be refracted to any direction in air by introducing an additional layer composed of dielectric rods at a photonic crystal surface. The refraction angle can be tuned from negative to positive value by adjusting the period of the additional layer. The refracted beam power can be also controllable by varying the radii of rods in the layer and the distance between the layer and the surface. The grating-induced omnidirectional refraction of self-collimated beams could provide an efficient way to manipulate light propagation and increase the possibility of application of self-collimated beams.

Self-collimation-based photonic crystal Mach–Zehnder demultiplexer

“…The dielectric constant and the radius of the rods are  = 12 and = r a 0.35 , respectively, where a denotes the lattice constant. In our previous works, it was shown that the self-collimation phenomenon occurs when E-polarized light beams, which have electric fields parallel to the rod axis, with frequencies approximate to = f c a 0.194 ( ), propagate in the GM-direction (the (11)-direction in real space) in a PC with the same structural parameters as those considered in this study [16,23]. Moreover, an asymmetric MZI based on the selfcollimation effect has been proposed and realized in experiment [25].…”

“…Since Kosaka et al demonstrated the self-collimation phenomenon of light beams in a PC [12], various self-collimation-based PC devices have been proposed and demonstrated, such as beam splitters [13][14][15][16], interferometers [17,18], polarization beam splitters [19,20], directional emitters [21,22], grating couplers [23], filters [24][25][26][27], and slow light devices [28][29][30]. Due to the unique and beneficial light-guiding properties such as diffractionless propagation along a definite direction [31,32] and easy crossing without crosstalk [33], optical devices based on the self-collimated beams have intrinsic potential for realizing high-density photonic integrated circuits.…”

Efficient coupling of self-collimated beams to slow light modes of a coupled zigzag-box resonator via antireflection structures in a photonic crystal

“…The phenomenon of self-collimated propagation of a light beam in a photonic crystal (PC) has attracted great interest in the past few years because of its favorable light guiding properties, such as diffractionless propagation in a definite direction and easy crossing without cross talk [7][8][9][10][11][12]. Various PC devices, such as beam splitters [13][14][15], interferometers [16][17][18], resonators [19,20], polarization beam splitters [21,22], directional emitters [23,24], and grating couplers [25] have been proposed based on the self-collimation effect. Very recently, we numerically and experimentally investigated the resonant transmission of self-collimated beams through coupled zigzag-box resonators (CZBRs) in a PC, and found that the speed of a self-collimated beam can be significantly reduced [26,27].…”