ORCID Profile
0000-0002-7065-0987
Current Organisation
Nanyang Technological University
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Publisher: Wiley
Date: 22-11-2022
Abstract: Metasurfaces supporting optical bound states in the continuum (BICs) are emerging as simple and compact optical cavities to realize polarization-vortex lasers. The winding of the polarization around the singularity defines topological charges which are generally set by the cavity design and cannot be altered without changing geometrical parameters. Here, a subwavelength-thin phase-change halide perovskite BIC metasurface functioning as a tunable polarization vortex microlaser is demonstrated. Upon the perovskite structural phase transitions, both its refractive index and gain vary substantially, inducing reversible and bistable switching between distinct polarization vortexes underpinned by opposite topological charges. Dynamic tuning and switching of the resulting vector beams may find use in microscopy imaging, particle trapping and manipulation, and optical data storage.
Publisher: Wiley
Date: 14-02-2022
Abstract: The Rashba effect, i.e., the splitting of electronic spin‐polarized bands in the momentum space of a crystal with broken inversion symmetry, has enabled the realization of spin‐orbitronic devices, in which spins are manipulated by spin–orbit coupling. In optics, where the helicity of light polarization represents the spin degree of freedom for spin–momentum coupling, the optical Rashba effect is manifested by the splitting of optical states with opposite chirality in the momentum space. Previous realizations of the optical Rashba effect relied on passive devices determining the surface plasmon or light propagation inside nanostructures, or the directional emission of chiral luminescence when hybridized with light‐emitting media. An active device underpinned by the optical Rashba effect is demonstrated here, in which a monolithic halide perovskite metasurface emits highly directional chiral photoluminescence. An all‐dielectric metasurface design with broken in‐plane inversion symmetry is directly embossed into the high‐refractive‐index, light‐emitting perovskite film, yielding a degree of circular polarization of photoluminescence of 60% at room temperature.
Publisher: Wiley
Date: 23-11-2022
Abstract: Emerging immersive visual communication technologies require light sources with complex functionality for dynamic control of polarization, directivity, wavefront, spectrum, and intensity of light. Currently, this is mostly achieved by free space bulk optic elements, limiting the adoption of these technologies. Flat optics based on artificially structured metasurfaces that operate at the sub‐wavelength scale are a viable solution, however, their integration into electrically driven devices remains challenging. Here, a radically new approach to monolithic integration of a dielectric metasurface into a perovskite light‐emitting transistor is demonstrated. It is shown that nanogratings directly structured on top of the transistor channel yield an 8‐fold increase of electroluminescence intensity and dynamic tunability of polarization. This new light‐emitting metatransistor device concept opens unlimited opportunities for light management strategies based on metasurface design and integration.
Publisher: American Chemical Society (ACS)
Date: 02-05-2023
Publisher: Springer Science and Business Media LLC
Date: 23-03-2022
DOI: 10.1038/S41467-022-29253-0
Abstract: Recent attempts to synthesize hybrid perovskites with large chirality have been h ered by large size mismatch and weak interaction between their structure and the wavelength of light. Here we adopt a planar nanostructure design to overcome these limitations and realize all-dielectric perovskite metasurfaces with giant superstructural chirality. We identify a direct spectral correspondence between the near- and the far- field chirality, and tune the electric and magnetic multipole moments of the resonant chiral metamolecules to obtain large anisotropy factor of 0.49 and circular dichroism of 6350 mdeg. Simulations show that larger area metasurfaces could yield even higher optical activity, approaching the theoretical limits. Our results clearly demonstrate the advantages of nanostructrure engineering for the implementation of perovskite chiral photonic, optoelectronic, and spintronic devices.
No related grants have been discovered for Jingyi Tian.