Unconventional iNtegrated nanophotonIc sources with Quantum correlations

Latest Publications

Spontaneous symmetry breaking in a coherently driven nanophotonic Bose-Hubbard dimer

B. Garbin, A. Giraldo, K. J. H. Peters, N. G. R. Broderick, A. Spakman, F. Raineri, A. Levenson, S. R. K. Rodriguez, B. Krauskopf, A. M. Yacomotti

arXiv:2108.01655 (2021)

We report on the first experimental observation of spontaneous mirror symmetry breaking (SSB) in coherently driven-dissipative coupled optical cavities. SSB is observed as the breaking of the spatial or mirror Z2 symmetry between two symmetrically pumped and evanescently coupled photonic crystal nanocavities, and manifests itself as random intensity localization in one of the two cavities. We show that, in a system featuring repulsive boson interactions (U > 0), the observation of a pure pitchfork bifurcation requires negative photon hopping energies (J < 0), which we have realized in our photonic crystal molecule. SSB is observed over a wide range of the two-dimensional parameter space of driving intensity and detuning, where we also find a region that exhibits bistable symmetric behavior. Our results pave the way for the experimental study of limit cycles and deterministic chaos arising from SSB, as well as the study of nonclassical photon correlations close to SSB transitions.

Direct observation of zero modes in a non-Hermitian nanocavity array

Flore Hentinger, Melissa Hedir, Bruno Garbin, Mathias Marconi, Li Ge, Fabrice Raineri, Ariel Levenson, and Alejandro M. Yacomotti

arXiv:2108.09672 (2021)

Zero modes are symmetry protected ones whose energy eigenvalues have zero real parts. In Hermitian arrays, they arise as a consequence of the sublattice symmetry, implying that they are dark modes. In non-Hermitian systems, that naturally emerge in gain/loss optical cavities, particle-hole symmetry prevails instead; the resulting zero modes are no longer dark but feature π/2 phase jumps between adjacent cavities. Here we report on the direct observation of zero modes in a non-Hermitian three coupled photonic crystal nanocavity array containing quantum wells. Unlike the Hermitian counterparts, the non-Hermitian zero modes can only be observed for small sublattice detuning, and they can be identified through far-field imaging and spectral filtering of the photoluminescence at selected pump locations. We explain the zero mode coalescence as a parity-time phase transition for small coupling. These zero modes are robust against coupling disorder, and can be used for laser mode engineering and photonic computing.

Mesoscopic limit cycles in coupled nanolasers

M. Marconi, F. Raineri, A. Levenson, A. M. Yacomotti, J. Javaloyes, S. H. Pan, A. El Amili, and Y. Fainman

Phys. Rev. Lett. 124, 213602 (2020)

Two coupled nanolasers exhibit a mode switching transition, theoretically described by mode beating limit cycle oscillations. Their decay rate is vanishingly small in the thermodynamic limit, i.e., when the spontaneous emission noise tends to zero. We provide experimental statistical evidence of mesoscopic limit cycles (~10^3 intracavity photons). Specifically, we show that the order parameter quantifying the limit cycle amplitude can be reconstructed from the mode intensity statistics. We observe a maximum of the averaged amplitude at the mode switching, accounting for limit cycle oscillations. We finally relate this maximum to a dip of mode cross-correlations, reaching a minimum of g^{(2)}_{ij}=2/3, which we show to be a mesoscopic limit. Coupled nanolasers are thus an appealing test bed for the investigation of spontaneous breaking of time translation symmetry in the presence of strong quantum fluctuations.

The driven-dissipative Bose-Hubbard dimer: phase diagram and chaos

A. Giraldo, B. Krauskopf, N. G. R. Broderick, J. A. Levenson and A. M. Yacomotti

New J. Phys. 22 043009 (2020)

We present the phase diagram of the mean-field driven-dissipative Bose-Hubbard dimer model. For a dimer with repulsive on-site interactions (U>0) and coherent driving we prove that ℤ2-symmetry breaking, via pitchfork bifurcations with sizable extensions of the asymmetric solutions, require a negative tunneling parameter (J<0). In addition, we show that the model exhibits deterministic dissipative chaos. The chaotic attractor emerges from a Shilnikov mechanism of a periodic orbit born in a Hopf bifurcation and, depending on its symmetry properties, it is either localized or not.

Generating strong anti-bunching by interfering nonclassical and classical states of light

R. Boddeda , Q. Glorieux, A. Bramati and S. Pigeon

J. Phys. B: At. Mol. Opt. Phys. 52 (2019) 215401

We study a simple setup which offers the possibility to generate quantum states of light with very small g(2)(0), a signature of strong anti-bunched light. This can be achieved by mixing on a beamsplitter a coherent state with a nonclassical state, such as a squeezed state, and even with a bunched state [g(2)(0)>1] such as a Schrödinger cat state. We elucidate the interference mechanism generating such strong anti-bunching and relate it to the unconventional photon blockade. We also detail how this effect can be applied to detect weakly squeezed states of light.

Localization control of few-photon states in parity-symmetric 'photonic molecules' under balanced pumping

C. D. B. Bentley, A. Celestino, A. M. Yacomotti, R. El-Ganainy and A Eisfeld

New J. Phys. 20 (2018) 063008

We theoretically investigate the problem of localization control of few-photon states in driven-dissipative parity-symmetric photonic molecules. We show that a quantum feedback loop can utilize the information of the spontaneously-emitted photons from each cavity to induce asymmetric photon population in the cavities, while maintaining a balanced pump that respects parity symmetry.