Goos–H?nchen shifts in reflective phase-gradient-produced metasurfaces

We studied Goos–H?nchen(GH) shifts on a reflective phase-gradient-produced metasurface. Their analytical solutions were achieved for both TE and TM polarizations utilizing the generalized Snell's law. The calculated results show that the GH shifts are evidently affected by phase gradients and incident angles, which means that a certain range of GH shifts can be realized as long as an incident angle, phase gradient, and frequency are properly chosen. This offers an effective method for the control of GH shifts.     

Resonant tunneling and enhanced Goos–Hänchen shift in a graphene double velocity barrier structure

Resonant transmission and Goos–Hänchen (GH) shift for Dirac fermion beams tunneling through graphene double velocity barrier structures (DVBs) are investigated theoretically. Analytical and numerical results demonstrate that strong resonant tunneling effect occurs in this structure and is highly dependent on the incident angle and the structure of velocity barriers. The resonant tunneling in graphene DVBs belongs to the Fabry–Pérot resonance and leads to oscillated conduction at wide energy range. It is also found that GH shifts in this structure can be enhanced by the resonant tunneling and multi-GH shift peaks with giant magnitudes can occur at these resonant energy positions. These special properties of GH shifts in graphene DVBs may have good application in lateral manipulation of electron beams and valley or spin beam splitter.     

Zero,positive and negative quantum Goos–Hänchen shifts in graphene barrier with vertical magnetic field

We have explored the zero, positive and negative quantum Goos–Hänchen (GH) shifts of the transmitted Dirac carriers in graphene through a potential barrier with vertical magnetic field. Numerical results show that only one energy position at the zero GH shift exists and is highly dependent on the y-directional wave vector, the energy gap, the magnetic field and the potential. The positive and negative GH shifts happen when the incident energy is more and less than the energy position at the zero GH shift, respectively. In addition, we found that there are two values of potential at the zero GH shifts, where a potential window can always keep the positive GH shifts. These results may be useful in designing a graphene-based valley or spin splitter as well as manipulating the electrons and holes in graphene nanostructure.     

Temperature dependence of the surface-plasmon-induced Goos–H?nchen shifts

Optical sensing of temperature variations is explored by studying the Goos–H?nchen (GH) lateral shift of a reflected light beam from various device based on the surface plasmon (SP) excitation at metal-dielectric interfaces. Both the Kretchman and the Sarid geometry will be considered, where the temperature variations of the GH shifts associated with excitation of both the regular and the long-range SP will be studied. It is found that while the SP-induced shifts and their temperature sensitivities are much greater than those from a bare metallic surface, these sensitivities are comparable between the shifts induced by the different kinds of SP, although the long-range SP can in general induce much greater values in the GH shifts, as reported recently in the literature.     

Nonlinear Goos–Hänchen shifts of reflected light from inhomogeneous Kerr-like slabs

We investigate the Goos–Hänchen (GH) shifts of reflected light from Kerr-like slabs, whose permittivities are inhomogeneous in space as well as light intensity dependent. The GH shifts exhibit bistable, multivalued properties or a more complicated hysteretic response to the input light intensity, and the different spatial dependences of the permittivity have a great effect on the hysteretic response. The bistable or multivalued GH shifts can be modulated by various parameters, such as the angle of incidence and the thickness of slab.     

Space–time cloaks through birefringent Goos–H?nchen shifts

We report a theoretical demonstration for the creation of space–time holes based on birefringence of reflection,transmission, and the Goos–H?chen(GH) shifts from a chiral medium. We observed space–time holes in the reflection, transmission, and their corresponding GH-shifted beams. Two space–time holes are clearly detected in the regions of 0 t ≤ 5τ_0 and-5 w ≤ y ≤ 5 w, as well as in the regions of-5τ_0≤ t ≤ 0 and-5 w ≤ y ≤ 5 w.These space–time holes hide objects and information contents from observers and hackers. The objects and information contents are completely undetectable, and thus events can be cloaked. The results of this paper have potential applications in the invisibility of drone technology and secure communication of information in telecom industries.     

Controllable Goos-Hänchen shift in graphene triangular double barrier

We study the Goos-Hänchen (GH) shifts for Dirac fermions in graphene scattered by a triangular double barrier potential. The massless Dirac-like equation was used to describe the scattered fermions by such potential configuration. Our results show that the GH shifts is affected by the geometrical structure of the double barrier. In particular the GH shifts change sign at the transmission zero energies and exhibit enhanced peaks at each bound state associated with the double barrier when the incident angle is less than the critical angle associated with total reflection.     

Goos–Hänchen shift for higher-order Hermite–Gaussian beams

We study the reflection of a Hermite–Gaussian beam at an interface between two dielectric media. We show that unlike Laguerre–Gaussian beams, Hermite–Gaussian beams undergo no significant distortion upon reflection. We report Goos–H?nchen shift for all the spots of a higher-order Hermite–Gaussian beam near the critical angle. The shift is shown to be insignificant away from the critical angle. The calculations are carried out neglecting the longitudinal component along the direction of propagation for a spatially finite, s-polarized, full 3D vector beam. We briefly discuss the difficulties associated with the paraxial approximation pertaining to a vector Gaussian beam.     

Comparison of Goos–Hänchen shifts of the reflected beam from graphene on dielectrics and metals

The Goos–Hänchen shifts of the reflected beam from graphene-on-dielectric (or metal) in the optical wavelength are investigated by using the stationary-phase method. For the graphene-on-dielectric substrates, it is found that the pseudo-Brewster angle and Goos–Hänchen shift are influenced greatly by the introduced graphene sheets for TM polarization. By changing number of graphene sheets, the lateral shifts can be large positive or negative near the pseudo-Brewster angle. For TE polarization, the lateral shift is still small; however it can also be positive or negative by changing the number of graphene sheets. For the graphene-on-metal substrates, graphene sheets exert a great impact on the reflectance while has little effect on the lateral shifts of both polarizations. Finally, the role of the graphene sheets on the lateral shifts for the different visible wavelengths is discussed.     

Giant Goos–Hnchen shifts of waveguide coupled long-range surface plasmon resonance mode

A hybrid structure based on a planar waveguide(PWG) mode coupling a long-range surface plasmon resonance(LRSPR) mode is proposed to enhance the GH shift. Both the PWG mode and LRSPR mode can be in strong resonance, and these two modes can be coupled together due to the normal-mode splitting. The largest GH shift of PWG-coupled LRSPR structure is 4156 times that of the incident beam, which is 23 times and 3.6 times that of the surface plasmon resonance(SPR) structure and the LRSPR structure, respectively. As a GH shift sensor, the highest sensitivity of 4.68 × 10~7λ is realized in the coupled structure. Compared with the sensitivity of the traditional SPR structure, the sensitivity of our structure is increased by more than 2 orders, which theoretically indicates that the proposed configuration can be applied to the field of high-sensitivity sensors in the future.     

Goos-Hänchen shift in bilayer graphene

The quantum Goos-Hänchen (GH) shift of an electron (massive Dirac fermion) at a potential step in bilayer graphene is investigated. We show that the GH shift depends on the step height, the kinetic energy of the electron and incident angle. It is found that the GH shift can be large (positive or negative) under the suitable conditions.     

Tunable Bistability in the Goos–H?nchen Effect with Nonlinear Graphene

We present a planar model system of a silica covered with a monolayer of nonlinear graphene to achieve a tunable Goos–H?nchen(GH) shift in the terahertz range. It is theoretically found that the transition between a negative shift and a large positive one can be realized by altering the intensity of incident light. Moreover, by controlling the chemical potential of graphene and the incident angle of light, we can further control the tunable GH shift dynamically. Numerical simulations for GH shifts based on Gaussian waves are in good agreement with our theoretical calculations.     

Effects of strain on Goos–Hänchen-like shifts of graphene

We have studied the Goos–Hänchen-like (GHL) shifts for massless Dirac electrons passing across a potential barrier in strained graphene. The analytical solutions of the transmission coefficient and the GHL shifts are obtained. The GHL shifts as the function of the strain tensor and direction, the incidence angle and the barrier's width are discussed. We also explore how critical angles change as the strain tensor and incidence electron energy change. Finally, we make a proposal of experimental measurement of the GHL shifts. The study of the GHL shifts will make for applications in graphene-based nano-electronics.     

Frustrated Total Internal Reflection: Resonant and Negative Goos–Hänchen Shifts in Microwave Regime

It is well-known that the variations of Goos–Hänchen shifts (GHSs) are closely associated with the energy flux provided by evanescent states in the case of total internal reflection. However, when the frustrated total internal reflection (FTIR) is realized with double-prism system operated in the microwave frequency, we observe that the GHSs for the reflected beam show periodic, resembling the phenomenon for transmitted beams reported in the literatures, versus either the operating frequency or the air layer thickness, which is different from the variation of the corresponding reflected energy. Moreover, in another FTIR based system fabricated by a composite absorptive material slab with a two-dimensional top layer of frequency selective surface (FSS), the GHSs for reflected beam are discovered as not only resonant but also negative with the incidence of transverse electric that is TE polarized, just as predicted theoretically in the literatures.     

Goos–Hänchen Shift from Cold and Hot Atomic Media Using Kerr Nonlinearity

We study and examine the Goos–Hänchen shifts of a propagating probe light field in a four-level tripodtype cold and hot atomic medium. The behavior of Goos–Hänchen shifts is studied in reflection and transmission beams in the presence of the coherent Kerr effect and the Doppler broadening effect. We observe that these shifts can be controlled by the relative propagation direction of the control field to that of the probe field.     

Enhancement of the Goos–Hänchen shift by electromagnetically induced transparency with amplification

The manipulation of the Goos–Hänchen (GH) shifts of the reflected and transmitted probe beams through a cavity containing ?-configuration artificial or realistic atomic medium is investigated. Adjusting the coherent control fields of atomic medium, the electromagnetically induced transparency with amplification (EITA) can be yielded. When the frequency of probe beam is around EITA, the negative as well as positive GH shifts of the reflected and transmitted probe beams can be greatly enhanced by EITA. Meantime, the GH shift can be switched between the considerably large positive and negative values by adjusting the collective phase of the external fields.     

On the Goos–Hänchen Effect in the Case of Excitation of Surface Waves in the Kretschmann Scheme

Optics and Spectroscopy - A theoretical method for investigating reflection of a finite-aperture plane light beam from a flat-layered structure in the Kretschmann scheme is considered. The...