Dynamically measuring the holo-information of light fields in three-dimensional space using a periodic polarization-structured light

Spatially structured light field has attracted great attention due to its novel properties and application potential in numerous fields.Among them,the most striking one is the polarization-structured light,known as the vector beam.Here,using a periodic polarization-structured light,we propose a method to dynamically measure the holo-information of light fields,including the amplitude,phase,and polarization distributions,in three-dimensional(3D)space.The measurement system is composed of a Mach-Zender interferometer involving a liquid crystal polarized grating in the reference arm,which is simple,stable,and easy to operate.Featuring the single-shot measurement,this method supports observing the dynamic variation of object light fields.The accuracy,3D polarimetry,and dynamic observation of this method are validated by measuring a calibrated quarter-wave plate,a vector vortex beam,a Poincarébeam,and a stressed polymethyl methacrylate sample.

λ/20-Thick cavity for mimicking electromagnetically induced transparency at telecommunication wavelengths

Optical cavities play crucial roles in enhanced light-matter interaction,light control,and optical communications,but their dimensions are limited by the material property and operating wavelength.Ultrathin planar cavities are urgently in demand for large-area and integrated optical devices.However,extremely reducing the planar cavity dimension is a critical challenge,especially at telecommunication wavelengths.Herein,we demonstrate a type of ultrathin cavities based on large-area grown Bi_(2)Te_(3)topological insulator(TI)nanofilms,which present distinct optical resonance in the near-infrared region.The result shows that the Bi_(2)Te_(3)TI material presents ultrahigh refractive indices of>6 at telecommunication wavelengths.The cavity thickness can approach 1/20 of the resonance wavelength,superior to those of planar cavities based on conventional Si and Ge high refractive index materials.Moreover,we observed an analog of the electromagnetically induced transparency(EIT)effect at telecommunication wavelengths by depositing the cavity on a photonic crystal.The EIT-like behavior is derived from the destructive interference coupling between the nanocavity resonance and Tamm plasmons.The spectral response depends on the nanocavity thickness,whose adjustment enables the generation of obvious Fano resonance.The experiments agree well with the simulations.This work will open a new door for ultrathin cavities and applications of TI materials in light control and devices.

Cylindrical vector beam generator on photonic crystal cavity integrated with metal split ring nanoresonators

We propose a chip-integratable cylindrical vector[CV]beam generator by integrating six plasmonic split ring resonators[SRRs]on a planar photonic crystal[PPC]cavity.The employed PPC cavity is formed by cutting six adjacent air holes in the PPC center,which could generate a CV beam with azimuthally symmetric polarizations.By further integrating six SRRs on the structure defects of the PPC cavity,the polarizations of the CV beam could be tailored by controlling the opening angles of the SRRs,e.g.,from azimuthal to radial symmetry.The mechanism is governed by the coupling between the resonance modes in SRRs and PPC cavity,which modifies the far-field radiation of the resonance mode of the PPC cavity with the SRR as the nano-antenna.The integration of SRRs also increases the coupling of the generated CV beam with the free-space optics,such as an objective lens,promising its further applications in optical communication,optical tweezer,imaging,etc.

Subwavelength optical localization with toroidal excitations in plasmonic and Mie metamaterials

Since the performance of electronic circuits is becoming rather limited in face of intensively increasing of amount of information and related operations,alloptical processing offers a promising strategy for future information system.It would benefit a great deal if the all-optical processing could be implemented within the developed electronic chips of nanoscale structures.In that it is highly desirable to break the diffraction limit of light for achieving effective light manipulations with deep subwavelength structures compatible with the state-of-the-art nanofabrication processes.It is of fundamental importance to get subwavelength optical localization,that is,squeeze light wave into subwavelength space for achieving freely manipulating of light fields.This review summarizes the development in realizing subwavelength optical localization by exciting toroidal mode in photonic metamaterials.The toroidal excitations in plasmonic metamaterials and Mie resonant metamaterials,in 3D structures and planar metamaterials,with single or few layers in spectral regime from microwave to optical frequencies are surveyed.Based on the discussion on the configurations of toroidal excitations,the recent development on toroidalrelated optical scattering control actively manipulates the toroidal excitations,and promising applications are further investigated and highlighted.

Perfect light absorption in monolayer MoS;empowered by optical Tamm states

We present the perfect light absorption of monolayer molybdenum disulfide(MoS_(2))in a dielectric multilayer system with two different Bragg mirrors.The results show that the strong absorption of visible light in monolayer MoS_(2) is attributed to the formation of optical Tamm states(OTSs)between two Bragg mirrors.The MoS_(2) absorption spectrum is dependent on the layer thickness of Bragg mirrors,incident angle of light,and the period numbers of Bragg mirrors.Especially,the nearly perfect light absorption(99.4%)of monolayer MoS_(2) can be achieved by choosing proper period numbers,which is well analyzed by the temporal coupled-mode theory.