Spin-to-orbital angular momentum conversion in semiconductor microcavities

Abstract

We experimentally demonstrate a technique for the generation of optical beams carrying orbital angular momentum using a planar semiconductor microcavity. Despite being isotropic systems with no structural gyrotropy, semiconductor microcavities, because of the transverse-electric-transverse-magnetic polarization splitting that they feature, allow for the conversion of the circular polarization of an incoming laser beam into the orbital angular momentum of the transmitted light field. The process implies the formation of topological entities, a pair of optical vortices, in the intracavity field.

Helicity and angular momentum: A symmetry-based framework for the study of light-matter interactions

“…4], [13, Figs. 2(c)-(d)] and [14], and that the underlying reason for their appearance is not SAM to OAM transfer, but that the electromagnetic duality symmetry is broken in those systems.…”

“…The conversion between spin and orbital angular momentum is widely used to explain phase singularities in numerical simulations of tightly focused fields [9][10][11], and in scattering experiments: [12][13][14]. A detailed discussion of the SAM to OAM conversion can be found in [30].…”

“…Strongly non-paraxial tightly focused light fields are the bread and butter of applications where light is made to interact with nano-structures, molecules and atoms. The mechanism of spin to orbit angular momentum conversion (SAM to OAM), also referred to as spin-orbit interaction, is the explanation of choice for numerically obtained observations in focusing [9][10][11] and remarkable results in scattering experiments [12][13][14]. For example, the presence of optical vortices in tightly focused fields and in scattered fields is explained by conversions between the two types of angular momenta.…”

“…In systems with a high degree of symmetry, like a sphere or a planar multilayer system, a wise choice of basis simplifies condition (14). The symmetries of those two systems make the TE and TM multipoles [19, chap.…”

Parabolic polarization splitting of Tamm states in a metal-organic microcavity

“…Recently, much attention has been paid to a study of the possible generation of optical states possessing non-zero orbital angular momentum, which could find applications in quantum information processing. 12 Initially, microcavities were entirely realized with semiconductors, but recently it has been shown that the inclusion of metallic layers in a microcavity is interesting both for fundamental effects and applications: It was shown that the introduction of metallic components into a microcavity leads to the appearance of additional localized optical states, so called Tamm plasmons, 13 which can strongly couple to cavity polaritons. 14 In dielectric microcavities, metal layers can play numerous roles simultaneously: they lead to the appearance of Tamm plasmons and determine their eigenenergies and can be used to contact and control the properties of the device electrically.…”