2P fluorescence imaging of hippocampal neurons in mice using hollow core fiber based endoscopes

International audienc

Etude structurale et spectroscopique de boites quantiques InAs/InP pour la réalisation d'un VECSEL bi-fréquence

National audienceNous développons un nouveau type de dispositif photonique consistant en une source laser bi-fréquence unique, combinant à la fois haute finesse spectrale, faible bruit et haute puissance, en vue de bénéficier de fréquence de battement dans le régime THz. L’originalité réside dans l’utilisation conjointe d’une architecture de type VECSEL (Vertical External Cavity Surface Emitting Laser) et d’une zone active à boites quantiques InAs/InP, présentant un gain avec un fort caractère inhomogène. Dans ce cadre, il est nécessaire de jouer sur la densité et la largeur homogène des boites quantiques. Nous montrons ici via des caractérisations spectroscopiques (photoluminescence et saturation du gain) et structurales comment ces paramètres peuvent être contrôlés

VECSEL bi-fréquences cohérent : vers une source THz compacte

National audienceNous proposons un nouveau type de dispositif photonique permettant de concevoir une source laser bi-fréquence unique, combinant à la fois haute finesse spectrale, faible bruit et haute puissance, en vue de bénéficier de fréquence de battement dans le régime THz. L'originalité réside dans l'utilisation conjointe d'une architecture de type VECSEL (Vertical External Cavity Surface Emitting Laser) et d'une zone active à boites quantiques InAs/InP, présentant un gain avec un fort caractère inhomogène. Son développement s'appuie sur des caractérisations spectroscopiques (photoluminescence, saturation du gain) et structurales dont nous présentons les résultats préliminaires

1.5 µm Quantum Dots Spectral Hole Burning experiments for dual frequency laser engineering

International audienceThe Terahertz (THz) frequency domain is attractive for numerous applications including phonon spectroscopy, radio-astronomy, imaging, sensing and communication. Nevertheless the development of a compact, tunable, electrically driven room-temperature source operating in the THz band frequency [1-5 THz] remains a challenge. An alternative to low-temperature-cooled Quantum Cascade Lasers is the widely investigated photomixing technique which relies on semiconductor antenna fed by two laser fields beating at the targeted THz frequency. When a highly coherent CW emission is mandatory, a single laser cavity sustaining the oscillation of the two required laser fields is a very attractive approach. Indeed, the phase noises of the two optical fields being inherently correlated, the beatnote exhibits a high spectral purity. Following this paradigm, dual-frequency Quantum Wells (QWs) based Vertical External Cavity Surface Emitting Lasers (VECSELs) architectures have been successfully demonstrated [1][2][3]. Nevertheless, because of the inherent homogeneously broadened gain of QWs, the two laser modes suffer from strong coupling making it necessary to lift the spatial degeneracy inside the active medium. Moreover, the frequency detuning remains lower than in Quantum Dots (QDs). Accordingly, we have been exploring over the past years the benefits of using wider and potentially less homogeneously broadened gain medium such as Quantum Dots. To this aim, InAs QDs are grown on InP (311B) substrate, and characterized by photoluminescence and atomic force microscopy. The density (from 10^10 to 10^11 cm-2) and the size of QDs are carefully engineered while keeping a 1550 nm emission wavelength. To evaluate the potential of QDs for dual frequency oscillation, a critical parameter is the homogeneous linewidth. It is measured through Spectral Hole Burning (SHB) experiments using two tunable and continuous-wave lasers. In order to be as close as possible to the laser operation conditions, the SHB experiments are performed at high temperature levels and high carrier densities. In this talk, we will present our preliminary results from Spectral Hole Burning experiments conducted on both InAs/InP QDs and conventional InGaAs/InP QWs. The dedicated homemade measurement apparatus will be presented as well. This work is supported by the IDYLIC ANR project (ANR-15-CE24-0034-01)

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

International audienceWe 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. In addition, an extension of the model makes it possible to evaluate the influence of different mode profiles in the cavity as well as the spatial diffusion of the carriers and/or the inhomogeneity of the temperature. These results are in very good agreement with previous experimental results, showing the independence of C with respect to the beating frequency and its evolution versus the spatial mode splitting in the gain medium

Spectral Hole Burning Spectroscopy on Quantum Dashes and Quantum Dots for Dual-Frequency Laser Engineering

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1545 nm Quantum Dot Vertical Cavity Surface Emitting Laser with low threshold

International audienc

High-power InAs quantum dot VECSEL with fundamental mode emission at 1.5 µm (Conference Presentation)

International audienc

Mode Coupling Measurement in Dual-Frequency Quantum Well-based VECSEL

International audienc

High-power InAs quantum dot VECSEL emitting at 1.5 µm

International audienc