Self-collimation effects in photonic crystals are generally investigated by employing flat equifrequency contours. Here we report, based on a partially flat equifrequency contour inducing two different group velocity vectors, the simultaneous excitation of dual self-collimated beams and the selective excitation of either of them by varying the incident angle or the width of an input Gaussian beam. With combination of the finite-difference time-domain simulation and the Fourier analysis as well as the wave vector diagram, we analyze the refractive behaviors of these self-collimated Bloch waves.
|Journal||Applied Physics Letters|
|State||Published - 2006|