Realization of Exciton‐Mediated Optical Spin‐Orbit Interaction in Organic Microcrystalline Resonators

Abstract

The ability to control the spin‐orbit interaction (SOI) of light in optical microresonators is of fundamental importance for future photonics. Organic microcrystals, due to their giant optical anisotropy, play a crucial role in spin‐optics and topological photonics. Here, the controllable and wavelength‐dependent Rashba–Dresselhaus (RD) SOI is realized that is attributed to the anisotropic excitonic response in an optical microcavity filled with an organic microcrystalline. This work investigates the transition of the spin‐splitting from twice winding caused by the splitting of the transverse‐electric and transverse‐magnetic modes to once winding caused by the RD effect. The interplay of the two allows engineer the SOI of light in organic microcavities, which besides its fundamental interest promises applications in spin‐controlled on‐chip integrated nanophotonic elements, toward exploiting nonmagnetic and low‐cost spin‐photonic devices.

Circularly polarized electroluminescence from a single-crystal organic microcavity light-emitting diode based on photonic spin-orbit interactions

“…In theory, such a birefringent microcavity can be approximately described by an effective Hamiltonian , where describes the intrinsic transverse-electric-transverse-magnetic (TE-TM) splitting of the cavity modes 45 , is the RD Hamiltonian 33 , 34 , 46 , giving rise to a spin-splitting along direction with the strength , and is the Hamiltonian representing the XY splitting 45 , i.e., the energy splitting ( at ) of the perpendicularly linearly polarized modes (X- and Y-polarizations) with opposite parity (here, we define it as β 0 = E X − E Y , where E X and E Y are the ground state energies of X and Y modes of opposite parity). The above effective Hamiltonian in the circular polarization basis can be written in the form of a 2 × 2 matrix: where is the energy of the ground state, is the effective mass of cavity photons, is the strength of the TE-TM splitting, and ( ∈[0, 2 ]) is the polar angle.…”

“…Contrary to inorganic materials, organic molecular assemblies, especially organic single crystals (OSCs), have highly ordered and anisotropic molecular packing arrangement and therefore anisotropic refractive index and show birefringence. Recently, the tunability of both energy and polarization of the confined photonic modes have been reported in liquid-crystal-filled 33 and OSC-filled 34 birefringent organic cavities. In particular, when two photonic modes with orthogonal linear-polarization and opposite parity are close to resonance, Rashba-Dresselhaus (RD) SOI emerges with the characteristic feature of left- and right-handed CP dispersions 33 , 34 .…”

“…Recently, the tunability of both energy and polarization of the confined photonic modes have been reported in liquid-crystal-filled 33 and OSC-filled 34 birefringent organic cavities. In particular, when two photonic modes with orthogonal linear-polarization and opposite parity are close to resonance, Rashba-Dresselhaus (RD) SOI emerges with the characteristic feature of left- and right-handed CP dispersions 33 , 34 . Regrettably, the CP-splitting phenomenon due to RD-SOI is demonstrated in most cases in passive reflection mode.…”

Electrically tunable Berry curvature and strong light-matter coupling in liquid crystal microcavities with 2D perovskite

“…This leads to a double winding effective magnetic field in the cavity plane that grows quadratically in the photon in-plane momentum ( 35 ). Recently, the photonic analog of the electronic Dresselhaus ( 36 ) and Rashba-Dresselhaus (RD) ( 37 , 38 ) SOCs have been realized in microcavities. For the case of cavities that host both RD SOC and TE-TM splitting, it has been shown theoretically that reducing the cavity symmetry could form local concentrations of the Berry curvature ( 39 ) without the need to break time-reversal symmetry through external magnetic fields acting on the excitonic component of polaritons ( 11 , 40 , 41 ) or nonzero optical activity for the photons ( 28 , 42 ).…”

Electrically tunable Berry curvature and strong light-matter coupling in birefringent perovskite microcavities at room temperature

“…This leads to a double winding effective magnetic field in the cavity plane which grows quadratically in the photon in-plane momentum [35]. Recently, photonic analogue of the electronic Dresselhaus [36], and Rashba-Dresselhaus [37,38] SOCs have been realized in microcavities. For the case of cavities that host both Rashba-Dresselhaus (RD) SOC and TE-TM splitting it has been shown theoretically that reducing the cavity symmetry could form local concentrations of Berry curvature [39] without the need to break time reversal symmetry through external magnetic fields acting on the excitonic component of polaritons [11,40,41] or nonzero optical activity for the photons [28,42].…”