Optical switching of a nonlinear slab in total internal reflection state

Levon S. Aslanyan, N. N. Badalyan, Andranik Petrosyan +2 more

Yuan-Ping Cai, Li 丽 Jiang 姜, Ren-Gang Wan

Abstract We investigate the nonlinear Goos–Hänchen shift of a light beam reflected from a prism-coupled leaky waveguide containing a Kerr medium. As the incident power varies, the system can switch between two states, total internal reflection and frustrated total reflection, owing to the inherent positive feedback arising from the intensity-dependent guiding mode resonance. The reflectance exhibits optical bistability; meanwhile, the lateral shift of the reflected beam also shows hysteresis behavior. It is found that the transition between the two stable states is related to the excitation of a leaky mode in the waveguide, which results from the modulation of the electric field in the nonlinear substrate. We also analyze the effects of system parameters on the bistable Goos–Hänchen shift. The thresholds as well as the width of the hysteresis curve are sensitive to the thicknesses of the gap layer and the guiding layer, which determine the resonance angle. The bistable lateral displacement in the slab waveguide may have potential applications in optical switching, beam steering, etc.

Sunaina Sunaina, Somendu Jana

I. C. Khoo, Jingya Hou

A nonlinear thin film bounded by two dielectric media could act as an optical switching and bistability device, owing to two physical mechanisms at work near the total internal reflection state. One is the simple intensity-dependent index change induced by the finite optical field in the film before transmission occurs, and the other is the nonlinear Fabry-Perot interference associated with the high reflectivities at the two interfaces when transmission takes place. We present a detailed theory for these two mechanisms and for the case in which the nonlinearity is also nonlocal (e.g., in a liquid-crystal film). The results for multiple switchings and hysteresis hold in general for any nonlinear thin film.

H. Haug, L. Bányai

I. C. Khoo, Jingya Hou

A nonlinear thin film bounded by two dielectric media can act as an optical switching bistable device owing to two mechanisms at work near the total internal reflection state. One is the intensity-dependent index change induced by the optical field in the thin film before transmission occurs, and the other is the nonlinear Fabry-Perot interference associated with the high reflectivities at the two interfaces just after transmission takes place.