RESUMEN
We report lasing of moiré trapped interlayer excitons (IXs) by integrating a pristine hBN-encapsulated MoSe2/WSe2 heterobilayer into a high-Q (>104) nanophotonic cavity. We control the cavity-IX detuning using a magnetic field and measure their dipolar coupling strength to be 78 ± 4 micro-electron volts, fully consistent with the 82 micro-electron volts predicted by theory. The emission from the cavity mode shows clear threshold-like behavior as the transition is tuned into resonance with the cavity. We observe a superlinear power dependence accompanied by a narrowing of the linewidth as the distinct features of lasing. The onset and prominence of these threshold-like behaviors are pronounced at resonance while weak off-resonance. Our results show that a lasing transition can be induced in interacting moiré IXs with macroscopic coherence extending over the length scale of the cavity mode. Such systems raise interesting perspectives for low-power switching and synaptic nanophotonic devices using two-dimensional materials.
RESUMEN
We report on the spatial coherence of interlayer exciton ensembles as formed in MoSe_{2}/WSe_{2} heterostructures and characterized by point-inversion Michelson-Morley interferometry. Below 10 K, the measured spatial coherence length of the interlayer excitons reaches values equivalent to the lateral expansion of the exciton ensembles. In this regime, the light emission of the excitons turns out to be homogeneously broadened in energy with a high temporal coherence. At higher temperatures, both the spatial coherence length and the temporal coherence time decrease, most likely because of thermal processes. The presented findings point towards a spatially extended, coherent many-body state of interlayer excitons at low temperature.