Efficient excitation of self-collimated beams and single Bloch modes in planar photonic crystals

Efficient excitation of self-collimated beams and...

Field profile in a waveguide (a) located above a photonic crystal and coupled to the latter so as to excite a self-collimated beam (b).

Abstract:
Using finite-difference time-domain calculations, we investigate out-of-plane coupling between a square-lattice planar photonic crystal and a conventional waveguide located above the photonic crystal. We couple a waveguide oriented in the ΓX direction to a photonic crystal mode in the second band and show that anticrossing takes place. In this way, a self-collimated beam is launched in the planar photonic crystal, with full power transfer. Furthermore, we investigate the coupling between a waveguide oriented in the ΓM direction and a photonic crystal and show that single photonic crystal modes can be selectively excited.
J. Witzens, and A. Scherer, Efficient excitation of self-collimated beams and single Bloch modes in planar photonic crystals, J. Opt. Soc. Am. A 20, 935-940 (2003).