Arbitrary Achromatic Polarization Control with Reconfigurable Metasurface Systems

• Published in: Laser & photonics reviews Vol. 17; no. 7
• Main Authors: Wang, Evan W., Yu, Shang‐Jie, Phan, Thaibao, Dhuey, Scott, Fan, Jonathan A.
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.07.2023; Wiley Blackwell (John Wiley & Sons)
• Subjects: Bandwidths; Birefringence; Broadband; Control systems; Dynamic control; Interferometers; Lateral displacement; metagrating; Metasurfaces; Poincare spheres; Polarization; Reconfiguration; Topology optimization
• ISSN: 1863-8880; 1863-8899
• DOI: 10.1002/lpor.202200926

Dynamic control over the polarization state of light is foundational for many scientific and technological applications, yet it remains a challenge to dynamically tailor responses with arbitrary polarization bases over a broad bandwidth. Broadband metasurface systems that utilize microscale displacements between two metasurfaces to enable reconfigurable polarization responses within a predefined polarization basis are reported. The metasurface pairs form an interferometer, and the lateral displacements produce detour phase shifts within the interferometer beam paths that mediate polarization state tuning. It is shown how the metasurface systems can be designed using freeform topology optimization to enable tailorable elliptical birefringence responses over a large bandwidth and how cascaded metasurface systems can enable the mapping of input and output polarization states between any two points on the Poincare sphere. It is anticipated that these concepts will have utility in imaging, display, communications, and metrology applications in classical and quantum optical domains. Broadband metasurface systems, comprising pairs of metagratings, which can exhibit arbitrary birefringence, are reported. The metasurface pairs operate as interferometers with beam paths that tune via microscale shear displacements between the devices, enabling systems with dynamically reconfigurable polarization responses. Individual devices are designed using freeform topology optimization to achieve tailorable broadband polarization control.