Quantum Noise in Nanolasers: A New Approach

The low power of nanolasers makes them particularly susceptible to quantum fluctuations arising from, e.g., spontaneous emission, which manifests as intensity fluctuations and laser field decoherence [1]. Traditionally, quantum noise has been included in classical rate equations through the addition of Langevin forces. The Langevin Approach (LA) is, however, inaccurate when the quantum noise fluctuations become comparable in size to the photon population [2]. Full quantum mechanical master equations (ME) inherently include quantum noise but are computationally feasible only for nanolasers containing a few emitters due to the rapid increase of the Hilbert space with emitter number. In the mesoscopic regime of tens to hundreds of emitters-an increasingly relevant regime with advances in nanophotonics [3]-alternative approaches are therefore needed.