We conduct a theoretical analysis of the massive and tunable Goos–Hänchen(GH) shift on a polar crystal covered with periodical black phosphorus(BP)-patches in the THz range. The surface plasmon phonon polaritons(SPPPs), which are coupled by the surface phonon polaritons(SPh Ps) and surface plasmon polaritons(SPPs), can greatly increase GH shifts.Based on the in-plane anisotropy of BP, two typical metasurface models are designed and investigated. An enormous GH shift of about-7565.58 λ_(0) is achieved by adjusting the physical parameters of the BP-patches. In the designed metasurface structure, the maximum sensitivity accompanying large GH shifts can reach about 6.43 × 10^(8) λ_(0)/RIU, which is extremely sensitive to the size, carrier density, and layer number of BP. Compared with a traditional surface plasmon resonance sensor, the sensitivity is increased by at least two orders of magnitude. We believe that investigating metasurface-based SPPPs sensors could lead to high-sensitivity biochemical detection applications.
Quasi-bound state in the continuum(QBIC)resonance is gradually attracting attention and being applied in Goos-Hänchen(GH)shift enhancement due to its high quality(Q)factor and superior optical confinement.Currently,symmetry-protected QBIC resonance is often achieved by breaking the geometric symmetry,but few cases are achieved by breaking the material symmetry.This paper proposes a dielectric compound grating to achieve a high Q factor and high-reflection symmetry-protectede QBIC resonance based on material asymmetry.Theoretical calculations show that the symmetry-protected QBIC resonance achieved by material asymmetry can significantly increase the GH shift up to-980 times the resonance wavelength,and the maximum GH shift is located at the reflection peak with unity reflectance.This paper provides a theoretical basis for designing and fabricating high-performance GH shift tunable metasurfaces/dielectric gratings in the future.
We investigate the band structure and Goos–Hänchen-like shift in ferromagnetic mass graphene junction modulated by the circularly polarized light.It is found that both spin and valley-related energy gaps can be opened by employing the circularly polarized light and the exchange field in mass graphene.The valley-polarized Goos–Hänchen-like shift can be identified in the presence of circularly polarized light,and the spin-polarized Goos–Hänchen-like shift can be realized with introduction of exchange field in mass graphene.Furthermore,the spin and valley polarization-related Goos–Hänchen-like shift can be achieved by combination of circularly polarized light and exchange field in mass graphene.It is hopeful that our work will be more conducive for future applications in graphene polarization transport devices.
This paper puts forward a novel method of measuring the thin period-structure-film thickness based on the Bloch surface wave(BSW) enhanced Goos–Hanchen(GH) shift in one-dimensional photonic crystal(1DPC). The BSW phenomenon appearing in 1DPC enhances the GH shift generated in the attenuated total internal reflection structure. The GH shift is closely related to the thickness of the film which is composed of layer-structure of 1DPC. The GH shifts under multiple different incident light conditions will be obtained by varying the wavelength and angle of the measured light, and the thickness distribution of the entire structure of 1DPC is calculated by the particle swarm optimization(PSO) algorithm.The relationship between the structure of a 1DPC film composed of TiO_(2) and SiO_(2) layers and the GH shift, is investigated.Under the specific photonic crystal structure and incident conditions, a giant GH shift, 5.1 × 10^(3) times the wavelength of incidence, can be obtained theoretically. Simulation and calculation results show that the thickness of termination layer and periodic structure bilayer of 1DPC film with 0.1-nm resolution can be obtained by measuring the GH shifts. The exact structure of a 1DPC film is innovatively measured by the BSW-enhanced GH shift.
We establish the beam models of Goos–H?nchen(GH)and Imbert–Fedorov(IF)effects in tilted Weyl semimetals(WSMs),and systematically study the influences of Weyl cone tilting and chemical potential on the GH and IF shifts at a certain photon energy 1.96 eV.It is found that the GH and IF shifts in tilted type-Ⅰand type-ⅡWSMs are both almost symmetric about the Weyl cone tilting.Meanwhile,the GH and IF shifts in type-I WSMs almost do not change with the tilt degree of Weyl cones,while those in type-ⅡWSMs are extremely dependent on tilt degree.These trends are mainly due to the nearly symmetric distribution of WSMs conductivities,where the conductivities keep stable in type-I WSMs and gradually decrease with tilt degree in type-II WSMs.By adjusting the chemical potential,the boundary between type-I and type-II WSMs widens,and the dependence of the beam shifts on the tilt degree can be manipulated.Furthermore,by extending the relevant discussions to a wider frequency band,the peak fluctuation of GH shifts and the decrease of IF shifts occur gradually as the frequency increases,and the performance of beam shifts at photon energy 1.96 eV is equally suitable for other photon frequencies.The above findings provide a new reference for revisiting the beam shifts in tilted WSMs and determining the types of WSMs.
Shuo-Qing LiuYi-Fei SongTing WanYou-Gang KeZhao-Ming Luo
