PECASE: Parity-Time Symmetric Nanophotonic Materials and Metamaterials
[Technical Report, Final Report]
LELAND STANFORD JUNIOR UNIVERSITY
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The aim of the program was to develop a new class of nanoscale optical components and devices capable of lossless, asymmetric,nonlinear, and non-reciprocal light propagation across wavelength and sub-wavelength scales. Key Accomplishments from 2014 to 2019 included 1 Design of nanoscale optical diodes 2 Design of nanoscale optical isolators 3 The first high-quality factor phase gradient metasurfaces 4 Design of PT-symmetric plasmonic apertures for polarization rotation 5 Design of broadband non-Hermitian metamaterials and 6 Enantioselective optical trapping. In the final year of the grant, key accomplishments include 1. Design and fabrication of the first high-quality high-Q factor phase gradient metasurfaces. These metasurfaces have Q-factors in the thousands, and enable arbitrary optical transfer functions like beam-steering, beam-splitting, and lensing. They lay the foundation for efficient nonlinear and electro-optic modulation of metasurfaces. 2. Design of power-limiting lenses based on high-Q metasurfaces. We designed high-Q lenses, and use the intrinsic nonlinearity of Si to modulate the focal intensity and focal length. These lenses operate in the near-infrared, and several high-Q resonances can be embedded in the structure for multiplexed operation. 3. A new method for self-isolated lasing, based on high-Q chiral metasurfaces. We designed a sub-micron-thick lasing cavity that is inherently protected from reflections. This device utilizes spin-selective selection rules in Raman lasers with a circularly-polarized pump. A signal with an arbitrary polarization state transmits with amplification in one direction, but its reflection is suppressed by approximately an order of magnitude in the metasurface cavity, resulting in isolation.