Modeling the Lamb mode-coupling constant of quantum well semiconductor lasers.

We theoretically compute the coupling constant C between two emission modes of an extended cavity laser with a multiple quantum-well active layer. We use an optimized Monte Carlo model based on the Markov chain that describes the elementary events of carriers and photons over time. This model allows us to evaluate the influence on C of the transition from a class A laser to a class B laser and illustrates that the best stability of dual-mode lasers is obtained with the former.

Direct measurement of the spectral dependence of Lamb coupling constant in a dual frequency quantum well-based VECSEL.

Spectral dependence of Lamb coupling constant C is experimentally investigated in an InGaAlAs Quantum Wells active medium. An Optically-Pumped Vertical-External-Cavity Surface-Emitting Laser is designed to sustain the oscillation of two orthogonally polarized modes sharing the same active region while separated in the rest of the cavity. This laser design enables to tune independently the two wavelengths and, at the same time, to apply differential losses in order to extract without any extrapolation the actual coupling constant.

Millimeter-wave near-field imaging with bow-tie antennas.

A near-field reflectometry experiment operating at 60 GHz is built in view of material and circuit inspection. Experiments are always obtained in constant height mode of operation. The bow-tie near-field probe acts mostly as a linearly-polarized electric dipole and allows strongly subwavelength resolution of ≈ λ/130.

Monte Carlo modeling of the dual-mode regime in quantum-well and quantum-dot semiconductor lasers.

Monte Carlo markovian models of a dual-mode semiconductor laser with quantum well (QW) or quantum dot (QD) active regions are proposed. Accounting for carriers and photons as particles that may exchange energy in the course of time allows an ab initio description of laser dynamics such as the mode competition and intrinsic laser noise. We used these models to evaluate the stability of the dual-mode regime when laser characteristics are varied: mode gains and losses, non-radiative recombination rates, intraband relaxation time, capture time in QD, transfer of excitation between QD via the wetting layer.

Mechanical equivalent of quantum heat engines.

Quantum heat engines employ as working agents multilevel systems instead of classical gases. We show that under some conditions quantum heat engines are equivalent to a series of reservoirs at different altitudes containing balls of various weights. A cycle consists of picking up at random a ball from one reservoir and carrying it to the next, thereby performing or absorbing some work.