Dynamic beam steering with semiconductor metasurfaces

Muhammad Alam
Queens University

Muhammad Alam web site

Abstract

Operation of conventional optical devices, for example lenses and mirrors depends on phase accumulation as light propagates through refractive materials. An emerging alternative is metasurface, which consists of ultrathin subwavelength optical elements. Tunable metasurfaces enable dynamical control of properties of light at a subwavelength scale and will be useful for many applications including beam steering, dynamical holography and tunable flat lenses. To date, most of the electrically tunable metasurfaces have been realized using free carrier modulation, and switching of thermo-optical, liquid crystal and phase change media. However, the highest performance and lowest loss discrete optoelectronic modulators exploit the electro-optic effect in multiple-quantum-well heterostructures. I will describe how successful adoption of quantum-well heterostructures for achieving tunability can over overcome the limitations of tunable metasurfaces reported to date. I will discuss numerical and experimental results that highlight the promise of this approach and the challenges which need to be overcome before this becomes a successful technology.

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