Study Of Metasurface-Based Photoluminescence Modulation And Optical Field Information Detection

Optical metamaterials are composed of artificial subwavelength structures,which are able to interact with electromagnetic fields and have unique optical response comparing to natural metallic or dielectric materials.The fascinating optical properties and giant potentials in optical manipulation of metamaterials have been attractive to researchers all the time.However,the realization of metamaterials usually involves complex three-dimensional nanostructures,which means difficulty in fabrication techniques and huge optical loss during light propagation in bulky materials.The mentioned disadvantages severely hindered the applications of metamaterials.Therefore,a kind of planer metamaterials in subwavelength thickness,or metasurfaces,brings new possibility in optical manipulation.Metasurfaces usually consist of single layer or few layers of planar structures,which is convenient to manufactured by standard process such as focus-ion-beam etching and e-beam lithography.The thin thickness of metasurface can avoid high loss and simultaneously maintain the optical modulation ability as metamaterials.Due to the outstanding capability in modulating amplitudes,polarizations and phases of light beams,the miniaturized and ultrathin metasurfaces are prospective in integrated systems for imaging,sensing,holography,optical communication and quantum information.During the ten years there have emerged a serial of inspiring works and breakthroughs.And one of the future directions is to realize multifunctional and multiplexed metasurfaces.In this dissertation,the research was aimed at the modulation capability of metasurfaces in optical intensity and phase.Both one-dimensional plasmonic metasurface and two-dimensional metasurface were studied from theorical calculations,full-wave simulation and experiments.First,the amplitude modulation was studied through the enhancement of photoluminescence via one-dimensional plasmonic metasurface integrated with perovskite nanocrystals.Next,the phase modulation was learned through the propagation of vortex interference field generated by polarization multiplexed dielectric metasurface.And based on the spin-dependent metasurface,we designed a metasurface demultiplexer capable of detecting multiple spin and orbital angular momenta simultaneously.(1)A broadband photoluminescence enhancement of perovskite nanocrystals was achieved by exploiting one-dimensional plasmonic metasurface consisting of aluminum nanogrooves array.The strong near-field optical localization associated with surface plasmon polaritons coupled emission effect generated by the nanogrooves array can significantly boost the absorption of perovskite nanocrystals and tailor the photoluminescence emissions.Moreover,the high efficiency photoluminescence of perovskite nanocrystals embedded in the polymer matrix layer on the top of plasmonic nanostructured surface can be maintained for more than three weeks.These results imply that plasmonic nanostructured surface is a good candidate to stably broadband enhance the photoluminescence intensity of perovskite nanocrystals and further promote their potentials in the application of visible-light-emitting devices.(2)Two-dimensional dielectric metasurface was studied to realize independent polarization-controlled phase modulation.The theory and design principle were based on the combination of waveguide phase and geometric phase,which were able to be independently controlled by the geometric sizes and in-plane orientation angles of structure unit.According to the mentioned design principle,a polarization multiplexed metasurface was fabricated to generate spin-dependent vortex beam superposition field.The propagation dynamics of balanced and unbalanced superposition field related with Gouy phase was studied both theoretically and experimentally.(3)Based on theorical analysis above,we introduce a novel detection approach for measuring multiple polarization and orbital angular momentum modes simultaneously through a planar nanophotonic demultiplexer based on an all-dielectric metasurface.Coaxial light beams carrying multiple polarization and orbital angular momentum states of light upon transmission through the demultiplexer are spatially separated into a range of vortex beams with different topological charge,each propagating along a specific wavevector.The broadband response,material dispersion and momentum conservation further enable the demultiplexer to achieve wavelength demultiplexing.We envision the ultracompact multifunctional architecture to enable simultaneous manipulation and measurement of polarization and spin encoded photon states with applications in integrated quantum optics and optical communications.