Quantum Statistics of Light Emitted from a Pillar Microcavity

A quantum behavior of the light emitted by exciton polaritons excited in a pillar semiconductor microcavity with embedded quantum well is investigated. Considering the bare excitons and photon modes as coupled quantum oscillators allows for an accurate accounting of the nonlinear and dissipative effects. In particular, using the method of quantum states presentation in a quantum phase space via quasiprobability functions (namely, a P-function and a Wigner function), we study the effect of the laser and the exciton-photon detuning on the second order correlation function of the emitted photons. We determine the conditions for the phenomena of bunching, giant bunching, and antibunching of the emitted light. In particular, we predict the effect of a giant bunching for the case of a large exciton to photon population ratio. Within the domain of parameters supporting a bistability regime we demonstrate the effect of bunching of photons.

Time-of-flight telemeter based on a ring-laser

We propose a new telemeter scheme for absolute distance measurements, based on a semiconductor ring laser, working in the bistability regime. The optical feedback provided by two external reflectors (a fixed one at short distance, and a moveable one defining the measuring arm) generates commutations of the propagation direction (clockwise, counter-clockwise) inside the ring laser, the period of which is linearly related to the distance of the measure arm reflector. A convenient electrical output signal can be easily obtained by a photodiode located behind the (partially reflecting) fixed mirror. This telemeter, which combines time-of-flight and optical injection, is very simple to implement, since, in addition to the laser, it only requires mirrors and collimation or focusing optics. Also electronic driving and processing are straightforward. Differently from most time-of-flight telemeters, this scheme does not require special provisions or processing to tackle the ambiguity problem. Simulations are performed by mathematical models based on rate-equations. This telemeter has been evaluated in the range 10 cm–32 m of round trip distance, with a fixed arm of 10 μm–10 cm, assuming typical literature parameters for a 1 mW ring laser.

Gaussian Quantum Trajectories for the Variational Simulation of Open Quantum-Optical Systems

We construct a class of variational methods for the study of open quantum systems based on Gaussian ansatzes for the quantum trajectory formalism. Gaussianity in the conjugate position and momentum quadratures is distinguished from Gaussianity in density and phase. We apply these methods to a driven-dissipative Kerr cavity where we study dephasing and the stationary states throughout the bistability regime. Computational cost proves to be similar to the Truncated Wigner Approximation (TWA) method, with at most quadratic scaling in system size. Meanwhile, strong correspondence with the numerically-exact trajectory description is maintained so that these methods contain more information on the ensemble constitution than TWA and can be more robust.