Amplified total internal reflection: theory, analysis, and demonstration of existence via FDTD

Keely J. Willis, John B. Schneider, Susan C. Hagness
2008 Optics Express  
The explanation of wave behavior upon total internal reflection from a gainy medium has defied consensus for 40 years. We examine this question using both the finite-difference time-domain (FDTD) method and theoretical analyses. FDTD simulations of a localized wave impinging on a gainy half space are based directly on Maxwell's equations and make no underlying assumptions. They reveal that amplification occurs upon total internal reflection from a gainy medium; conversely, amplification does
more » ... occur for incidence below the critical angle. Excellent agreement is obtained between the FDTD results and an analytical formulation that employs a new branch cut in the complex "propagation-constant" plane.
doi:10.1364/oe.16.001903 pmid:18542269 fatcat:3a6twwjhdfbnhld5hzhsklhkui