High-Q Whispering-Gallery-Modes Microresonators in the Near-Ultraviolet Spectral Range

High-$Q$ whispering gallery mode microresonators are cornerstones to develop compact coherent sources like single frequency lasers or frequency combs. This work reports a detailed characterization of a whispering gallery mode microsphere in the near ultraviolet. Light coupling in the resonator is obtain thanks to a robust angle-polished fiber allowing to investigate the different coupling regimes. An intrinsic $Q_0$-factor of $2.2 \times 10^8$ and a finesse of $7.3 \times 10^4$ are reported at a wavelength of 420 nm. Physical mechanisms contributing to the $Q_0$-factor are discussed and routes to improve the performances are drawn. Such high-$Q$ factor and high finesse are key ingredients to ease the study of photonic devices based on WGM microresonators.Comment: 6 pages, 6 figure

Stochastic resonance in collective exciton-polariton excitations inside a GaAs microcavity

We report the first observation of stochastic resonance in confined exciton-polaritons. We evidence this phenomena by tracking the polaritons behavior through two stochastic resonance quantifiers namely the spectral magnification factor and the signal-to-noise ratio. The evolution of the stochastic resonance in function of the modulation amplitude of the periodic excitation signal is studied. Our experimental observations are well reproduced by numerical simulations performed in the framework of the Gross-Pitaevskii equation under stochastic perturbation.Comment: Accepted for publication in Phys. Rev. Let

Nonlinear relaxation and selective polychromatic lasing of confined polaritons

Polaritons have often been proposed as promising candidates for the realization of all-optical devices due to the easy manipulation and control of their density and spin. In this paper we present a relaxation mechanism for confined polaritons and its application in a device based on polariton lasing in which the incoming monochromatic beam can be channeled into several polariton lasers at different wavelengths. Polaritons are injected in a 3 mu m diameter trap by an incoming beam slightly detuned with respect to a confined state, and the resulting optical bistability is then imprinted on the lower confined states through an efficient relaxation mechanism which combines phonon interaction and bosonic stimulation. Above threshold, all the confined states behave like lasers and the onset of coherence is demonstrated by spectral narrowing. Moreover, the initial polarization of the laser is conserved during the relaxation process allowing for spin logic operations. In this paper we demonstrate that, due to the nonlinear behavior, it is possible to switch ON and OFF the lasing from the confined states of the trap by tailoring the input beam. All the experimental findings are validated and very well reproduced in the framework of the generalized Gross-Pitaevskii equation

Composants et fonctions optiques Applications aux télécommunications et à l'émission de lumière

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Stabilisation d'une diode laser à cavité externe émettant à 420 nm sur un anneau de fibre

International audienceNous présentons un système d’asservissement compact et bas coût pour réduire le bruit de fréquence d’un laser ECDL à 420 nm. Notre approche, basée sur une cavité en anneau de fibre, mène à une réduction du bruit de fréquence proche de 30 dB qui se traduit par un affinement de la largeur de raie du laser intégrée sur 10 ms de 800 kHz à 36 kHz

Compact fiber-ring resonator for blue external cavity diode laser stabilization

We demonstrate a compact and low-cost all-fiber-based locking setup for frequencynoise suppression of a 420 nm external-cavity diode laser. Frequency noise reduction in the 100 Hz to 800 kHz range is demonstrated up to 40 dB associated with a linewidth narrowing from 850 kHz to 20 kHz for 10 ms integration time. This simple locking scheme might be implemented for a large range of wavelengths and can be integrated on a small footprint for embedded applications requiring narrow linewidth blue laser diodes

Low frequency noise blue external cavity diode laser

International audienc

Stabilisation d'une diode laser à cavité externe émettant à 420 nm sur un anneau de fibre

International audienceNous présentons un système d’asservissement compact et bas coût pour réduire le bruit de fréquence d’un laser ECDL à 420 nm. Notre approche, basée sur une cavité en anneau de fibre, mène à une réduction du bruit de fréquence proche de 30 dB qui se traduit par un affinement de la largeur de raie du laser intégrée sur 10 ms de 800 kHz à 36 kHz

Stabilisation d'une diode laser à cavité externe émettant à 420 nm sur un anneau de fibre

International audienc