Photon statistics and non-equilibrium dynamics in photonic crystal coupled nanolasers

Datum

22.02.2017

Zeit

16:30 - 17:30

Sprache

en

Hauptthema

Physik

Andere Themen

Physik

Host

Alejandro Giacomotti (CNRS Paris)

Beschreibung

We experimentally and theoretically investigate the non-linear dynamics of evanescently coupled nanolasers and its impact in terms of bifurcations and photon statistics. The nanolasers are fabricated in suspended 2D Photonic Crystal membranes, and studied as a function of pump power and coupling strength. The modification of coupling strength is obtained by an original engineering procedure that allows us to tune the coupling strength between the nanocavities without affecting the nanolaser performance [1]. I will focus on two experiments. In the first one, the cavities are pumped in a quasi-stationnary regime. For certain conditions, we are able to observe a paradigmatic classical bifurcation: the spontaneous mirror-symmetry breaking [1]. This is the first experimental demonstration of such transition in micro/nanophotonics. A pitchfork bifurcation reveals two localized states in the cavities. The symmetry breaking bifurcation has been observed with only ~150 intracavity photons, which makes this system promising to investigate non-classical photon correlations and nonlinear dynamical phenomena with few photons. In a second experiment, the nanolasers are pumped in a non-stationnary regime using short pulses [2] in order to investigate a new route for the generation and control of long tailed superthermal light. We analyze the heavy-tailed photon distributions (super-exponential) whose fluctuations are greater than those of thermal states and link, using a mean field model, both the emergence of the heavy tails and the superthermal nature of the nonlasing (symmetric, in-phase) mode. We show that passing through the lasing threshold corresponds to an abrupt decrease of the contribution of spontaneous emission —that plays the role of an effective temperature— during which the statistics of the nanolaser trajectories in phase space are dominated by nonlinear transport. Changing the duration of this out-of-equilibrium quenching phase, one obtains long-tailed distributions for the unstable in-phase mode in agreement with the experimental results.

Letztmalig verändert: 22.02.2017, 08:53:03