Tunable Spin dependent beam shift by simultaneously tailoring geometric and dynamical phases of light in inhomogeneous anisotropic medium

Abstract

Spin orbit interaction and the resulting Spin Hall effect of light are under recent intensive investigations because of their fundamental nature and potential applications. Here, we report an interesting manifestation of spin Hall effect of light and demonstrate its tunability in an inhomogeneous anisotropic medium exhibiting spatially varying retardance level. In our system, the beam shift occurs only for one circular polarization mode keeping the other orthogonal mode unaffected, which is shown to arise due to the combined spatial gradients of the geometric phase and the dynamical phase of light. The constituent two orthogonal circular polarization modes of an input linearly polarized light evolve in different trajectories, eventually manifesting as a large and tunable spin separation. The spin dependent beam shift and the demonstrated principle of simultaneously tailoring space-varying geometric and dynamical phase of light for achieving its tunability (of both magnitude and direction), may provide an attractive route towards development of spin-optical devices.

Laguerre–Gaussian modal q-plates

“…It should be mentioned that modal q plates are designed for a given azimuthal index l that cannot be switched to l by mere flip of the helicity of the incident light field, but flipping also the optical element along the propaga tion axis. Finally, we note that the proposed combined action of dynamic and geometrical phases towards the control of the radial degree of freedom of a light field represents another attempt to tailor the spatial properties of electromagnetic fields by hybrid phase transformations [48,49].…”

Quadrature Squeezing and Geometric-Phase Oscillations in Nano-Optics

“…Geometric phases are ubiquitous. They have been observed in a wide variety of optical/mechanical systems [1][2][3][4][5][6]. The geometric phases can be used as an excellent tool for analyzing the characteristics of optical phenomena because they reflect the geometries of quantum states with enormous generality.…”

“…The most familiar subject along these lines which the geometric phase plays a major role in, is fault-tolerant quantum computation of which operations are based on geometric phase gates [2]. Besides that, other disciplines in nano-optics, which adopt the geometric phases as a key factor, are geometric phase lenses [3], holograms [4], tunable beam-shift technology [5], virtual/augmented realities [6], etc.…”

Spin-selective scattering modes in a disordered anisotropic optical medium

“…In optics, coupling or interconversion of the spin angular momentum of a light beam (related to the polarization of light) with its orbital angular momentum (related to a helical or twisted wavefront) goes by the name of spin-orbit interaction (SOI) of light and is a topic of recent interest [1][2][3][4][5][6][7][8][9][10][11][12][13]. The conservation of the total angular momentum of a light beam leads to the generation of geometric phase and its spatial gradient, which is related to all the optical SOI phenomena in cyclic as well as noncyclic processes [1,[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Some of the very interesting effects arising from such ubiquitous interactions are the spin Hall effect (SHE) of light from a spatially tailored anisotropic medium, the optical Rashba effect, the spin-dependent scattering of light, etc.…”

“…Some of the very interesting effects arising from such ubiquitous interactions are the spin Hall effect (SHE) of light from a spatially tailored anisotropic medium, the optical Rashba effect, the spin-dependent scattering of light, etc. [1][2][3][4][5][6][7][8]10,11]. Moreover, the intriguing phenomenon has a wide range applications as it can offer a new direction towards the development of spin-controlled photonic devices ranging from the spin-controlled directionality to the spin-controlled orbital-angular-momentum generation [1][2][3][17][18][19].…”