The influence of light beam convergence on the stop-bands of a one-dimensional photonic crystal

Abstract

The infuence of beam convergence on the photonic band-gaps, or stop-bands (SBs), of one-dimensional photonic crystals (1D PCs) is investigated. The investigation is based on an analysis of the gap map obtained from re?ection spectra, calculated by the transfer matrix method for various angles of light incidence, and polarisations. The calculated data is compared with refection spectra taken using Fourier Transform Infrared microspectroscopy. It was found that the introduction of the parameter, ?' to account for the focused light beam, for angles up to 20?, has little effect on the first,or lowest SB and the SBs adjacent to it. However, an increase in the order of the SB causes an increase in the influence of this parameter.