Multiresonant Nonlocal Metasurfaces.

Area of Science:

• Optics and Photonics
• Metasurfaces
• Nanophotonics

Background:

• Optical metasurfaces with localized resonances offer wavefront shaping but suffer from limited spectral and angular control due to low quality (Q)-factor modes.
• Periodic nonlocal metasurfaces provide spectral and angular selectivity but lack fine spatial control.

Purpose of the Study:

• To develop multiresonant nonlocal metasurfaces that combine spectral filtering and wavefront shaping capabilities.
• To achieve simultaneous control over spectral, angular, and spatial properties of light.

Main Methods:

• Design of multiresonant nonlocal metasurfaces utilizing multiple resonances with varying Q-factors.
• Implementation of a highly symmetric array to achieve narrowband resonant transmission within a broadband resonant reflection window.
• Application of topology optimization for fabricating high-Q-factor metagratings for extreme wavefront transformations.

Main Results:

• Demonstration of simultaneous spectral filtering and wavefront shaping in the transmission mode.
• Realization of nonlocal flat lenses as compact band-pass imaging devices for microscopy.
• Achieved high-efficiency extreme wavefront transformations using topology-optimized metagratings.

Conclusions:

• Multiresonant nonlocal metasurfaces offer enhanced control over light's spatial and spectral properties.
• The developed flat lenses are suitable for compact, high-performance imaging systems in microscopy.
• This work advances the design of metasurfaces for sophisticated optical applications requiring precise wavefront control.