Beam steering via peak power decay in nonlinear waveguide arrays

Sotiris Droulias,Yaron Bromberg,Panagiotis Papagiannis,Yaron Silberberg,Yoav Lahini,Kyriakos Hizanidis,Yannis Kominis

doi:10.1088/1367-2630/15/9/093038

Abstract

We report the experimental observation and theoretical analysis of a novel beam-steering effect in periodic waveguide arrays that arises from the interplay between discrete diffraction, Kerr nonlinearity and any mechanism that effectively weakens the nonlinear part of the beam. In this regime the propagation direction shows increased sensitivity to the input angle and for a certain angular range around normal incidence a nonlinear beam may be guided to a direction opposite to that initially inserted. For continuous wave beams the role of this mechanism is played by absorption of any kind, such as three photon absorption, two photon absorption or even linear absorption. For pulsed beams we show that the same dynamics can arise due to strong normal temporal dispersion, while absorption is not necessary and can be a further enhancing or alternative factor. This observation falls under a more general dissipation-assisted beam velocity control mechanism in nonlinear optical lattices, which is also theoretically predicted by the effective particle approach.

Highlights

Current affiliationRestoring mechanism, non-negligible absorption may lead to an interesting dynamical behavior of a focused beam [19]
We report the experimental observation and theoretical analysis of a novel beam-steering effect in periodic waveguide arrays that arises from the interplay between discrete diffraction, Kerr nonlinearity and any mechanism that effectively weakens the nonlinear part of the beam
In this work we have showed how the interplay between discrete diffraction, Kerr nonlinearity and a mechanism that effectively weakens the nonlinear part of the beam along the propagation can result in counter-intuitive beam steering effects

Summary

Current affiliation

Restoring mechanism, non-negligible absorption may lead to an interesting dynamical behavior of a focused beam [19]. Recently it was shown that a pulsed beam propagating in a discrete system may lead to interesting patterns, such as discrete X-waves [20], which cannot be otherwise observed if the temporal dimension is either ignored or absent. Within this framework, in this work we observe experimentally and study numerically the spatiotemporal beam dynamics in periodic lattices and show how the temporal evolution may have a direct implication in the spatial propagation direction of light.

Experimental results

CW systems: simulations

Extension to CW systems with linear absorption or two photon absorption

Pulsed systems

Conclusions