Open AccessFree space diffraction on active gratings with balanced phase and gain/loss modulations
Author(s) -
Mykola Kulishov,
Bernard C. Kress
Publication year - 2012
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.20.029319
Subject(s) - optics , diffraction , amplitude , physics , phase (matter) , bragg's law , diffraction efficiency , fresnel diffraction , diffraction grating , symmetry (geometry) , asymmetry , phase modulation , phase noise , quantum mechanics , geometry , mathematics
A theoretical analysis of asymmetrical diffraction in Raman-Nath, intermediate and Bragg diffraction regimes is presented. The asymmetry is achieved by combining matched periodic modulations of the phase and of the loss/gain of the material, which enables the breakdown of optical symmetry and redirects all resulting optical energy in only positive or only negative diffraction orders, depending on the quarter period shift directions between the phase and the loss/gain modulations. Analytic expressions for the amplitudes of the diffraction orders are derived based on rigorous multimode coupled mode equations in slowly varying amplitude approximation.