Strongly coupled slow-light polaritons in one-dimensional disordered localized states

Cavity quantum electrodynamics advances the coherent control of a single quantum emitter with a quantized radiation field mode, typically piecewise engineered for the highest finesse and confinement in the cavity field. This enables the possibility of strong coupling for chip-scale quantum processing, but till now is limited to few research groups that can achieve the precision and deterministic requirements for these polariton states. Here we observe for the first time coherent polariton states of strong coupled single quantum dot excitons in inherently disordered one-dimensional localized modes in slow-light photonic crystals. Large vacuum Rabi splittings up to 311 {\mu}eV are observed, one of the largest avoided crossings in the solid-state. Our tight-binding models with quantum impurities detail these strong localized polaritons, spanning different disorder strengths, complementary to model-extracted pure dephasing and incoherent pumping rates. Such disorder-induced slow-light polaritons provide a platform towards coherent control, collective interactions, and quantum information processing.Comment: 17 pages, 5 figures and supplementary informatio

Second Harmonic Generation Enabled by Longitudinal Electric Field Components in Photonic Wire Waveguides

We investigate type I second harmonic generation in III-V semiconductor wire waveguides aligned with a crystallographic axis. In this direction, because of the single nonzero tensor element of III-V semiconductors, only frequency conversion by mixing with the longitudinal components of the optical fields is allowed. We experimentally study the impact of the propagation direction on the conversion efficiency and confirm the role played by the longitudinal components through the excitation of an antisymmetric second harmonic higher order mode

Theory of Slow Light Enhanced Four-Wave Mixing in Photonic Crystal Waveguides

The equations for Four-Wave-Mixing in a Photonic Crystal waveguide are derived accurately. The dispersive nature of slow-light enhancement, the impact of Bloch mode reshaping in the nonlinear overlap integrals and the tensor nature of the third order polarization are therefore taken into account. Numerical calculations reveal substantial differences with simpler models, which increase with decreasing group velocity. We predict that the gain for a 1.3 mm long, unoptimized GaInP waveguide will exceed 10 dB if the pump power exceeds 1 W.Comment: 6 pages, 4 figures; submitted to Optics Expres

Silicon-on-Insulator RF Filter Based on Photonic Crystal Functions for Channel Equalization

International audienceA compact silicon-on-insulator 2-tap interferometer is demonstrated as a channel equalizer. The radiofrequency filter is reconfigurable thanks to thermally-controlled photonic crystal couplers and delay lines. The channel fading of a dispersive fiber link supporting a directly modulated telecommunication signal is successfully compensated for using the interferometer, leading to eye diagram opening and the possibility to recover the bit-error-rate of a reference signal with less than 1-dB power penalty

Etude et réalisation de structures en cristaux photoniques pour les applications de traitement du signal optique

Mon travail de thèse a porté sur des structures guidantes de semi-conducteurs III-V à base de cristaux photoniques, dans le contexte du traitement de signaux portés optiquement. Elles sont obtenues par gravure sèche exploitant une nouvelle gravure de type "ICP" où la densité du plasma y est contrôlée indépendamment de l'énergie cinétique des ions réactifs. Nous avons d'abord réalisé des trous profonds de haut rapport d'aspect, utiles en vue de l'intégration monolithique de plusieurs fonctions. L'hétérostructure utilisée présente l'originalité de ne pas comporter d'aluminium. Des mesures ont validés la qualité des technologies choisies. A l'occasion de ces efforts technologiques nous avons proposé une méthode de réalisation de membranes en GaAs. Les membranes ont la particularité de permettre des modes sans pertes. Nous avons pu, en collaboration avec le LPN, définir des rubans de grande longueur (>1 mm) sur lesquels nous avons effectué des mesures de transmission. Nous avons mis en évidence (i) de très faibles pertes de propagation et (ii) la baisse de la vitesse de groupe dans les "modes lents", descendant à des vitesses de c/11. Nous avons montré que ces structures pouvaient induire sur des signaux de quelques GHz des retards de phase de quelques dizaines de degrés, déphasage qu'on contrôle par le choix de la porteuse. On peut penser ainsi à des délais contrôlables miniatures. Enfin, nous avons intégré une cavité au voisinage d'un tel guide et avons montré le transfert résonnant avec des facteurs de qualités en couplage de ~28000, dont l'analyse suggère qu'ils correspondent à des facteurs de qualités intrinsèque de 43000, sensiblement à l'état de l'art mondial.My PhD work was focused on III-V semiconductor guiding structures based on photonic crystals in the context of microwave signal processing for optical carriers. We fabricate them by dry etching techniques, exploiting a new etching technique known as ICP : the plasma density is controlled independently from the ion kinetic energy. We first realised deeply etched holes with a large aspect ratio, useful in view of monolithic integration of a plurality if functions. The particular heterostructure used for supporting photonic crystals is GaInP/GaAs/GaInP, an aluminium-free stack. Measurements did validate these technology synergies. During these technological efforts in TRT, we proposed a method for realising suspended GaAs membranes with high perfection. Although membranes are challenging when it comes to integration with other functions, they specifically give rise to quasi lossless modes when branches of the dispersion diagram may lie below the light line . A collaboration with LPN made it possible to define long guides (> 1mm), whose transmission could be safely measured. Exploiting the results, we evidenced (i) very low losses and (ii) a decrease in group velocity down to c/11. Correspondingly, we showed that these structures were indeed able to induce substantial dephasings (tens of degrees) onto GHz signals, dephasing that could be controlled in future miniature delay lines. Finally, we have integrated a cavity in the vicinity of such a guide, and we could evidence the resonant transfer with a coupled quality factor of ~28000 . Analysis further suggests that they correspond to intrinsic quality factors of 43000, hence at level with worldwide state-of-the-art.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Fano lines in the reflection spectrum of directly coupled systems of waveguides and cavities: Measurements, modeling, and manipulation of the Fano asymmetry

We measured and analyzed reflection spectra of directly coupled systems of waveguides and cavities. The observed Fano lines offer insight on the reflection and coupling processes. Very different from side-coupled systems, the observed Fano line shape is not caused by the termini of the waveguide but by the coupling process between the measurement device fiber and the waveguide. Our experimental results and analytical model show that the Fano parameter that describes the Fano line shape is very sensitive to the coupling condition. A movement of the fiber well below the Rayleigh range can lead to a drastic change of the Fano line shape

A Highly Linear All Optical Gate Based on Coupled Photonic Crystal Cavities

International audienceA photonic crystal molecule is used as an all-optical gate to perform sampling of microwave signals. We demonstrate a very linear operation over a 50dB still with a 1.2mW power consumption

Dispersive-wave-based octave-spanning supercontinuum generation in InGaP membrane waveguides on a silicon substrate

We demonstrate the generation of an octave-spanning supercontinuum in InGaP membrane waveguides on a silicon substrate pumped by a 1550-nm femtosecond source. The broadband nature of the supercontinuum in these dispersion-engineered high-index-contrast waveguides is enabled by dispersive wave generation on both sides of the pump as well as by the low nonlinear losses inherent to the material. We also measure the coherence properties of the output spectra close to the pump wavelength and find that the supercontinuum is highly coherent at least in this wavelength range.SCOPUS: ar.jinfo:eu-repo/semantics/publishe