OSE Seminars
Engineerable Phased-Array Sources Based on Nonlinear Metamaterial Nanocavities
Presented by Dr. Salvatore Campione, Center for Integrated Nanotechnologies (CINT), Sandia National Laboratories
We propose a new concept for phased-array sources at infrared frequencies based on the second harmonic generation capacity of metamaterial nanocavities strongly coupled to a highly nonlinear semiconductor heterostructure comprising intersubband transitions in quantum wells (QWs). This system is attractive for the manipulation of the direction, shape, and polarization of optical beams. The metamaterial nanocavity is designed to support both a fundamental resonance and an orthogonally polarized resonance at the second harmonic frequency. The asymmetric QW structure is designed to provide a large second order susceptibility. Optical pumping of the nanocavity induces a localized, phase-locked, nonlinear resonant polarization that acts as a source feed for a higher order resonance of the nanocavity. Varying the nanocavity design enables the production of beams with arbitrary shape and polarization. Due to the sub-wavelength extent of our QW structure, we are not limited by phase matching conditions as one would have for a conventional nonlinear crystal. Upon continuous wave illumination at the fundamental frequency we observe second harmonic signals in both the forward and backward directions. We achieve very efficient overall second harmonic generation given the deep sub-wavelength dimensions of the QW structure (at mid-infrared, about 1/15th of the free space wavelength of 10 μm). We also demonstrate two second harmonic phased-array sources that perform two optical functions at the second harmonic wavelength (~5 μm): a beam splitter and a polarizing beam splitter. Such systems represent a viable strategy for designing easily fabricated phased-array sources across the entire infrared spectrum through proper choice of QW and nanocavity designs.
12:00 pm, Tuesday, November 10, 2015
Room 101, Center for High Tech Materials
Science and Technology Park - South Campus
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