Inhibition of light tunneling in waveguide arrays
By: Yaroslav Kartashov
From: Universitat Politecnica de Catalunya, Spain
At: Instituto de Investigação Interdisciplinar, B3-01
[2011-02-24]
We describe theoretically and report on experimental observation of
almost perfect light tunneling inhibition at the edge and inside longitudinally-modulated laser-written waveguide arrays. When the refractive index of the guiding channels of array is harmonically modulated along the propagation direction and out-of-phase in adjacent guides, light is trapped in the excited waveguide over a long distance even in linear case due to resonances at specific modulation frequencies, which depend, in particular, on the depth of longitudinal refractive index modulation. The phenomenon can be used for tuning the localization threshold power in such z-modulated structures. We address light tunneling inhibition in both one- and two-dimensional settings. We also study an impact of nonlinearity on the width of resonances where tunneling inhibition is achieved. The nonlinearity broadens such resonances so that localization can take place even in detuned systems at power levels well below those required for nonlinearity-mediated localization in unmodulated systems. We also discuss how the structure and strengths of resonances in phenomenon of tunneling inhibition are affected by the law of longitudinal refractive index modulation.