Interaction-based nonlinear optics

by Dr. Avi Niv

Ben-Gurion University of the Negev
at Quantum optics seminar

Wed, 18 May 2022, 15:00
ZOOM only


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Nonlinear optics is the frequency conversion that light experiences while interacting with some system. As such, nonlinear optics cover a broad range of effects ranging from second-harmonic and sum and difference frequency generation important for lasers, material, and biological research; four-wave mixing for material characterization; high harmonic generation - an active research field in its own right; parametric oscillation and amplification used for lasers and related optics; Kerr effect for material characterization and optical communication, and much more. The origin of optical nonlinearity is traditionally thought to be a material property.
In the last couple of decades, much effort has been given to light-matter interactions at length scales smaller than the optical wavelength. The study of small-scale optics has sparked a renewed interest in nonlinear optics. Its ability to confine and manipulate light makes the initially weak nonlinearity a much stronger effect. Non the less, despite many exciting discoveries, advances, and new techniques, none has substantially surpassed what has already been achieved. The ruling paradigm during all this time has remained an intensified large-scale material-based nonlinearity.
The talk will show small-scale opportunities with no large-scale counterparts. Accordingly, we study nonlinear optics from deep subwavelength-sized domains with a predominantly linear response. We will show that these domains produce substantial nonlinear optical activity. Comparing our experimental findings to theory, we conclude that the observed nonlinearity is not a material property but emerges from electrostatic interaction between oscillating charges. Hence, it is termed interaction-based nonlinear optics. We propose a simple coupled oscillator model that captures the salient features of interaction-based nonlinear optics. We will use this model to explore parameter regimes outside our experimental reach, including intensified nonlinear response due to resonance excitation and the possibility of chaos.

Created on 16-05-2022 by Folman, Ron (folman)
Updaded on 16-05-2022 by Folman, Ron (folman)