Angular Goos-Hanchen Shifts Research Articles

Observation of Giant Angular Goos-Hanchen Shifts Enhanced by Surface Plasmon Resonance in Subwavelength Grating

The effect of the Goos-Hanchen (GH) angular shift for a visible light beam under the excitation of surface plasmon resonance (SPR) in a metal subwavelength grating has been investigated. Extremely large angular GH shifts have been demonstrated for a subwavelength grating with an optimal depth. The high sensitivity of the beam shape transformation and the GH shift to a change in the angle of incidence near the SPR has been shown by rigorous electromagnetic simulation and demonstrated experimentally. The focusing of the reflected beam near the subwavelength grating surface has been demonstrated.

Theoretical Study of Spatial and Angular Goos-Hänchen Shifts in Quantum System

The behavior of the spatial and angular Goos-Hanchen (GH) shifts for the reflected and transmitted probe light beams is theoretically investigated in a fixed geometrical configuration containing the three and then four – level quantum dot nanostructure. It is found that, by adjusting the controllable parameters such as Rabi frequencies of applied fields, the spatial and angular Goos-Hanchen shifts can be controlled containing both of the positive and negative shifts of reflected and transmitted probe light beams. Moreover, we find that the simultaneous superluminal or subluminal light reflected and transmitted probe beams can be obtained through the medium.

Angular Goos-Hänchen Shift Sensor Using a Gold Film Enhanced by Surface Plasmon Resonance.

We demonstrate the surface plasmon resonance (SPR)-enhanced angular Goos-Hänchen (GH) shift. Typical SPR-enhanced GH shift measurements make use of loosely collimated beams, which enhances only the spatial GH shift (ΔGH). Unlike this scheme, we focused the incident beam to a small beam waist to induce enhancement in the angular GH shift (ΘGH). Although this makes ΔGH negligible, the enhancement of ΘGH is much larger than the decrease in ΔGH. In order to excite surface plasmons, we employ a Kretschmann configuration using a simple gold (Au) film on a substrate. We show that although the efficiency of surface plasmon excitation is decreased by the focused geometry, a significantly large ΘGH was induced. With the simultaneous measurement of reflectivity for SPR and the beam shift for the GH shift used in this work, we experimentally show the potential of measuring enhanced ΘGH toward sensing application when the Au film is exposed to local environmental changes even in the simplest thin film structure.

Goos-Hänchen shifts due to graphene when intraband conductivity dominates

Abstract The conductivity of a monolayer graphene at intraband transitions is sensitive on the Fermi level and on the wavelength of the incident beam. Changing conductivity values through these parameters thus may offer better control of light impinging on graphene. In this paper, we investigate reflection, the simplest interaction of light on such surface, by looking at the Goos-Hanchen (GH) shift experienced by the incident light where the wavelength is at terahertz range. With this wavelength range, we assume that the carriers in graphene undergo intraband transition. We calculate that spatial and angular GH shifts can be present. For both GH shifts in general, we find that increasing the Fermi level changes the incident angle at which the maximum GH shifts arise. Moreover, we see that at higher frequencies, the amount of beam shift decreases with the Fermi level. At lower frequencies on the other hand, the shift becomes proportional to the Fermi level. Upon obtaining the measurable shifts, we find that the magnitude of the physical shifts can be easily detected given appropriate experimental parameters. Our results may increase the utility of graphene in optoelectronics devices and applications.

Goos–Hänchen shift for Gaussian beams impinging on monolayer-MoS2-coated surfaces

We report a detailed theoretical study of the Goos–Hanchen (GH) shift for a fundamental Gaussian beam on the surface coated with monolayer (ML) molybdenum disulfide (MoS2), a promising two-dimensional transition metal dichalcogenide (2D-TMDC) and a direct band-gap semiconductor. A general model has been developed to predict the GH shifts on ML-MoS2-coated surfaces for a light beam with different wavelengths. In contrast to the conventional GH shift, which is generally observed for total internal reflection, here we predict finite spatial and angular GH shift for both partial and total internal reflection conditions. Our analysis revealed that the observation of the giant negative spatial GH shift on MoS2-coated surfaces is attributed to the surface conductivity of the MoS2 ML, something that has never been explored. Furthermore, we find that the GH shifts are dependent on the mode of polarization, the wavelength of incident beam, and the nature of surfaces. This deepens our understanding of the unusual behavior of GH shift near Brewster’s angle as well as the critical angle of incidence. We expect that our findings will lead to several new applications of MoS2 in sensors and device technology.

LRSP resonance enhanced spatial and angular Goos–Hanchen shift and Imbert–Fedorov shift for Gaussian beam, Laguerre–Gaussian beam and Bessel beam

A new theoretical approach towards the composite effect of spatial and angular Goos–Hanchen (GH) shift and Imbert–Fedorov (IF) shift for the Gaussian beam, Laguerre–Gaussian beam and Bessel beam with long range surface plasmon (LRSP) resonance is observed, designed and simulated through the variation of incident angle at a wavelength of 1550nm where the four layered Kreschmann–Rather geometry comprises a ZnSe prism, a liquid crystal layer of E44 and two metal layers of silver. To the best of our knowledge several articles have been devoted, separately considering the Gaussian beam, Laguerre–Gaussian beam and Bessel beam without considering the effect of spatial and angular GH shift and IF shift whereas the exact output beam position can only be identified with the composite effect of these shifts. The investigation of these spatial and angular shifts for Gaussian beam and different orders of Laguerre–Gaussian beam are calculated and represented where these lateral shifts increase with the increment of the modes and further these lateral shifts for Bessel beam have also been analyzed. With this new approach various avenues expedite the way of futuristic applications in the field of fine tuning in optical switching with the accurate beam position using different beams.

Gate-voltage control of angular and spatial shifts for a dielectric slab containing graphene

By theoretically considering a dielectric slab containing graphene, we investigate the effect of the graphene layer on the angular Goos-Hanchen (AGH) shifts and the transverse angular and spatial shifts from the spin-Hall effect of light (SHEL) for the reflection of a light beam. Through manipulating the voltage applied to graphene via an exterior gate, it was found that near the transmission resonance of the slab containing graphene, the giant and tunable AGH shifts and transverse shifts (TS) for both s-polarized and p-polarized waves are present. We also find that near the normal incident angle, the giant and tunable TS from SHEL for both s-polarized and p-polarized waves can occur on the interface containing graphene. It is expected that these phenomena can result in significant interesting and novel applications of graphene in all kinds of optical devices, and more.

Giant and tunable Goos–Hanchen shifts for attenuated total reflection structure containing graphene

We investigate the effect of surface plasmon (SP) resonance on Goos–Hanchen (GH) spatial and angular shifts in the reflection of a light beam by considering an attenuated total reflection structure containing a graphene layer. In particular, we find giant spatial and angular GH shifts for the p-wave light close to the plasmon resonance. The GH shifts can be controlled by adjusting the voltage applied to graphene via external gate. The giant and tunable GH shifts provide an alternative SP sensing scheme, which improves the sensitivity of SP sensors significantly.