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9 September 2019 Ultrafast light-scattering dynamics of resonant semiconductor GaAs metasurfaces (Conference Presentation)
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Abstract
Active devices and nanoantennas are promising research area of nanophotonics. They can be used to build high-speed elements, optical switches, and sensors. The ultrafast all-optical switches can be represented as semiconductor metasurfaces and nanoantennas, which scattering properties are controlled using femtosecond laser pulses in the pump-probe technique. In this work, the ultrafast dynamics of the light scattering is experimentally investigated for phased arrays of asymmetric sub-wavelength GaAs super-cells consisting of resonators of the various sizes. Energy reallocation of the incident radiation into the different diffraction orders, controlled by the design of the metasurface, was obtained. This effect appears only for the resonant polarization for the structure, as well as at wavelengths close to the optimized value of 800-815 nm. Such energy reallocation is a sign of the phase-manipulation behavior of the metasurface. GaAs metasurfaces are studied by Fourier plane imaging microscopy, in which pump and probe signals of different diffraction orders can be measured independently. The transmission coefficient modulation โˆ†๐‘‡โ„๐‘‡ of the probe pulse in the first diffraction order is shown to be ~15% at a pump fluence of 0.02 ฮผJ/cm^2. The femtosecond relaxation time of free carriers in the GaAs metasurface is ~150 fs. These properties indicate that asymmetric GaAs nanoantennas can be used as all-optical switches.
Conference Presentation
© (2019) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Dmitry N. Gulkin, Vladimir O. Bessonov, Viacheslav S. Snigirev, Alexander S. Shorokhov, Irina V. Soboleva, and Andrey A. Fedyanin "Ultrafast light-scattering dynamics of resonant semiconductor GaAs metasurfaces (Conference Presentation)", Proc. SPIE 11122, Ultrafast Nonlinear Imaging and Spectroscopy VII, 1112202 (9 September 2019); https://doi.org/10.1117/12.2529453
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