Spin-Valley Atomically Thin Semiconductor Rashba Lasers

Direct-bandgap transition metal dichalcogenide (TMD) monolayers are appealing candidates to construct atomic-scale spin-optical light sources owing to their unique valley-contrasting optical selection rules. Here, the photonic Rashba effect is manifested as a spin-split dispersion in momentum space, which provides the opportunity to manipulate the valley degree of freedom. Previously, we achieved an incoherent photonic Rashba-type spin-split emission with peculiarities of spatial separation of the valley degree of freedom [1]. Recently, we further demonstrated a coherent classical spin-qubit Rashba laser with inherent phase correlations between the two valley pseudo-spins [2]. We also demonstrated a room-temperature valley-addressable Rashba monolayer laser in which the spin-symmetry breaking is realized in the absence of the magnetic field [3]. Our work provides a platform to further explore the atomic-scale spin optics, and it can also be an example to stimulate the development of more spin-optical devices utilizing the valley degree of freedom in the TMD monolayers.