Lupu Anatole, de Lustrac André, Ourir Abdelwaheb, Checoury Xavier, Lourtioz Jean-Michel, Centeno Emmanuel, Cassagne David, Albert Jean-Paul, Pommereau Frederic, Legouezigou Lionel, Drisse Olivier, Legouezigou Odile, Deroin Estelle, Duan Guang-Hua
Opt Express. 2006 Mar 6;14(5):2003-13. doi: 10.1364/oe.14.002003.
Experimental results on wavelength-dependent angular dispersion in InGaAsP triangular lattice planar photonic crystals are presented. An abrupt variation of the angular dispersion is observed for TM-polarized waves whose frequencies are comprised between those of the fourth and sixth allowed bands. According to the crystal period, the measured angle of refraction is found to either decrease or increase by 30 degrees within a wavelength range smaller than 30 nm. Experimental results are reproduced well from 2D finite difference time domain calculations. The observed phenomena are interpreted from the coupling of the incident light to different modes of the photonic crystal that travel with different group velocities and propagate in different directions within the crystal. Mode dispersion curves and mode patterns are calculated along with isofrequency curves to support this explanation. The observed discontinuous wavelength super-refraction opens a new approach to the application of superprisms.
