Inverse design of large-area metasurfaces
We present a computational framework for efficient optimization-based “inverse design” of large-area “metasurfaces” (subwavelength-patterned surfaces) for applications such as multi-wavelength/multi-angle optimizations, and demultiplexers. To optimize surfaces that can be thousands of wavelengths in...
| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
Optical Society of America
2018
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| Online Access: | http://hdl.handle.net/1721.1/119814 https://orcid.org/0000-0003-1647-4019 https://orcid.org/0000-0003-1219-0932 https://orcid.org/0000-0003-3605-6199 https://orcid.org/0000-0001-7327-4967 |
| Summary: | We present a computational framework for efficient optimization-based “inverse design” of large-area “metasurfaces” (subwavelength-patterned surfaces) for applications such as multi-wavelength/multi-angle optimizations, and demultiplexers. To optimize surfaces that can be thousands of wavelengths in diameter, with thousands (or millions) of parameters, the key is a fast approximate solver for the scattered field. We employ a “locally periodic” approximation in which the scattering problem is approximated by a composition of periodic scattering problems from each unit cell of the surface, and validate it against brute-force Maxwell solutions. This is an extension of ideas in previous metasurface designs, but with greatly increased flexibility, e.g. to automatically balance tradeoffs between multiple frequencies or to optimize a photonic device given only partial information about the desired field. Our approach even extends beyond the metasurface regime to non-subwavelength structures where additional diffracted orders must be included (but the period is not large enough to apply scalar diffraction theory). |
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