Measurement of azimuthal dependence of resonant coupling in 2D photonic crystals

An optical setup, inspired from that used for angle resolved reflective spectra measurement is used to determine photonic bands dispersion of 2D photonic crystals for all-around observation. The observation relies on coupling between the incoming beam and the photonic modes in periodically patterned planar structure, generating resonant features in the optical spectra. The features as a function of specific azimuthal angle lead to the determination of in-plane wave vector at a given frequency. To probe a performance of the photonic structures, the optical response of the photonic crystal in radiative region above light line was determined, and the structure of leaky modes for both polarization planesTE, TM at several incident angles was mapped. Leaky modes structure was approved by numerical RCWA-based modelling. The measured azimuthal dependences were evaluated to obtain equi-frequency curves. (C) 2017 Elsevier B.V. All rights reserved.