Emulation of the Spin—Orbit Coupling (SOC) in Optical Systems

Abstract

The similarity between GP equations, which provide MF (mean-field) models of the BEC dynamics and NLS equations in optics, suggests that many phenomena from the BEC realm may be emulated in optics, including spin-orbit coupling (SOC) [Bliokh et al. Nat. Photonics 9, 796808 (2015)]. In particular, it is possible to simulate SOC for matter waves in 2D systems by means of the light propagation in dual-core planar optical waveguides (couplers), with amplitudes of the electromagnetic waves in the two cores emulating two components of the spinor wave function in the SOC BEC. Each core carries the intrinsic Kerr (cubic) self-focusing nonlinearity. The similarity helps to elaborate optical setups which are capable to support stable 2D optical solitons in the spatiotemporal domain [Kartashov et al., Opt. Lett. 40, 10451048 (2015); Sakaguchi and Malomed, New J. Phys. 18, 105005 (2016)], in spite of the presence of the critical collapse in the same systems. The chapter also includes the presentation of findings for 1D solitons in the model of an optical coupler with the quintic intrinsic self-focusing, and in a PT-symmetric extension of the latter model, which includes mutually balanced gain and loss terms in the two cores of the coupler. In the latter model, the SOC emulation provides for stabilization of solitons of the Townes-soliton type, similar to what is found for 2D solitons in the case of the cubic self-focusing. This chapter is presented as a brief one, with the aim to produce characteristic examples of the SOC emulation in optics.