Luo Hai-Lu

Enhanced and Tunable Spin Hall Effect of Light upon Reflection of One-Dimensional Photonic Crystal with a Defect Layer

We show that the spin Hall effect of light upon reflection of one-dimensional photonic crystal with a defect layer can be enhanced significantly with a spin-dependent transverse displacement of the beam centroid of several wavelengths of light which is much larger than those reported previously, for horizontal- and vertical-polarization incidence. Under the condition of abrupt phase changes of reflection coefficients however, the spin Hall effect of light could be completely suppressed. Further, we demonstrate that, by tuning the optical parameters of the defect layer, the spin Hall effect of light upon reflection can be switchable for any incident angle and polarization of incidence.

Orbit-orbit interaction and photonic orbital Hall effect in reflection of a light beam

We examine the orbit—orbit interaction when a paraxial beam with intrinsic orbital angular momentum (IOAM) reflects at an air—glass interface. The orbital-dependent splitting of the beam intensity distribution arises due to the interaction between IOAM and extrinsic orbital angular momentum (EOAM). In addition, we find that the beam centroid shows an orbital-dependent rotation when seen along the propagation axis. However, the motion of the beam centroid related to the orbit—orbit interaction undergoes a straight line trajectory with a small angle inclining from the propagation axis. Similar to a previously developed spin-dependent splitting in the photonic spin Hall effect, the orbital-dependent splitting could lead to the photonic orbital Hall effect.

Focal Shift of Paraxial Gaussian Beams in a Left-Handed Material Slab Lens

Focal shift is inevitable in conventional lens systems due to the Fresnel number and angular aperture. In this Letter, we demonstrate that there is no focal shift when a paraxial Gaussian beam passes through a left-handed material slab lens without absorption or gain. However, the effect is exhibited in the presence of absorption or gain, and becomes larger as the absorption or gain increases. When the absorption is equal to the gain, the phenomenon of the focal shift caused by the gain is more obvious. In addition, the field distribution is not affected by the absorption or gain and always remains Gaussian both in internal and external focus planes.

Switching the direction of spin accumulation in the spin Hall effect of light by adjusting the optical axis of an uniaxial crystal

We theoretically and experimentally investigate a switchable spin Hall effect (SHE) of light in reflection near the Brewster angle at an air-uniaxial crystal interface. We find a large transverse spin splitting near the Brewster angle, whose sign can be altered by rotating the optical axis. As an analogy of the SHE in an electronic system, a switchable spin accumulation in the SHE of light is detected. We are able to switch the direction of the spin accumulation by adjusting the optical axis angle of the uniaxial crystal. These findings may give opportunities for photon spin manipulating and developing a new generation of nano-photonic devices.

Spin Hall effect of a light beam in anisotropic metamaterials

We theoretically investigate a switchable spin Hall effect of light (SHEL) in reflection for three specific dispersion relations at an air-anisotropic metamaterial interface. The displacements of horizontal and vertical polarization components vary with the incident angle at different dispersion relations. The transverse displacements can be obtained with the relevant metamaterial whose refractive index can be arbitrarily tailed. The results of the SHEL in the metamaterial provide a new way for manipulating the transverse displacements of a specific polarization component.

Focusing and phase compensation of paraxial Hermite-Gaussian and Laguerre-Gaussian beams by a negative refractive index material slab

According to angular spectrum representation, formalisms describing paraxial Hermite-Gaussian and Laguerre-Gaussian beams propagating through an isotropic negative refractive index material (NIM) slab are presented. Focusing and phase compensation of paraxial Hermite-Gaussian and Laguerre-Gaussian beams by the slab are investigated. The phase difference of beams caused by Gouy phase shift in air can be compensated by the inverse Gouy phase shift in NIM, thus the phase difference between the object plane and the image equals to zero in certain matching conditions. If conditions of focusing and phase compensation are satisfied simultaneously, intensity and phase distribution at object plane can be reconstructed at the image plane.

Integral Equation Method for Electromagnetic Wave Propagation in Stratified Anisotropic Dielectric-Magnetic Materials

X iv :1 00 4. 46 95 v2 [ ph ys ic s. op tic s] 1 7 M ay 2 01 0 Integral equation method for the electromagnetic wave propagation in stratified anisotropic dielectric-magnetic materials SHU Wei-Xing , FU Na, LV Xiao-Fang, LUO Hai-Lu, WEN Shuang-Chun, and FAN Dian-Yuan Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education, School of Computer and Communications, Hunan University, Changsha 410082, China Abstract We investigate the propagation of electromagnetic waves in stratified anisotropic dielectricmagnetic materials using the integral equation method (IEM). Based on the superposition principle, we use Hertz vector formulations of radiated fields to study the interaction of wave with matter. We derive in a new way the dispersion relation, Snell’s law and reflection/transmission coefficients by self-consistent analyses. Moreover, we find two new forms of the generalized extinction theorem. Applying the IEM, we investigate the wave propagation through a slab and disclose the underlying physics which are further verified by numerical simulations. The results lead to a unified framework of the IEM for the propagation of wave incident either from a medium or vacuum in stratified dielectric-magnetic materials.We investigate the propagation of electromagnetic waves in stratified anisotropic dielectric-magnetic materials using the integral equation method (IEM). Based on the superposition principle, we use Hertz vector formulations of radiated fields to study the interaction of wave with matter. We derive in a new way the dispersion relation, Snells law and reflection/transmission coefficients by self-consistent analyses. Moreover, we find two new forms of the generalized extinction theorem. Applying the IEM, we investigate the wave propagation through a slab and disclose the underlying physics, which are further verified by numerical simulations. The results lead to a unified framework of the IEM for the propagation of wave incident either from a medium or vacuum in stratified dielectric-magnetic materials.