Tunable, CW laser emission at 225 nm via intracavity frequency tripling in a semiconductor disk laser

Numerous applications would benefit from a compact laser source with tunable, continuous-wave emission in the deep ultraviolet (wavelengths <250nm); however, very few laser sources have been demonstrated with direct emission in this spectral region and options are generally limited to pulsed, fixed wavelength sources or complex and impractical setups for nonlinear frequency mixing of the emission of several infrared lasers in various external enhancement cavities. Here we propose an all-solid-state, continuous-wave, tunable laser with emission between 224 nm and 226 nm via intracavity frequency tripling in an AlGaInP-based semiconductor disk laser (SDL). Output power up to 78 µW is achieved in CW operation, with a tuning range over 350 cm-1. AlGaInP-based SDLs may be designed to emit anywhere between ~640 – 690 nm such that wavelengths between 213 nm and 230 nm may be targeted for specific applications using a similar set-up. An in-depth study of the nonlinear conversion has been carried out to understand the limitations of the set-up, namely large walk-off angles for phase-matching in the nonlinear crystals, and the potential for increasing the output power to several milli-Watts. This is, to the authors' knowledge, the first implementation of intracavity frequency tripling in a visible SDL and the shortest wavelength emitted from an SDL system

Orange emission in Pr3+-doped fluoroindate glasses

We synthesize and study the properties of praseodymium doped fluoroindate glasses. Glass compositions with praseodymium molar concentrations up to 5% were obtained with good optical quality. Thermal, optical, and luminescence properties are investigated. Judd–Ofelt analysis is used to determine radiative lifetime and emission cross-section of the orange transition originating from the 3P0 level. We find that these glasses are good candidates for the realization of blue diode laser pumped orange lasers for quantum information processing applications

Diode pumping of Nd:ASL and its frequency doubling for blue emission around 450 nm

International audienceWe present the diode pumping of a Nd-doped strontium and lanthanum (Nd:ASL) crystal Sr1-xLax-yNdyMgxAl12-xO19 (0.05 ≤ x ≤ 0.5; y = 0.05) for second harmonic generation around 450 nm. In order to fulfill the pumping requirements of this crystal, we have developed a high-brightness pump source based on a tapered amplifier in an extended cavity with a volume Bragg grating for wavelength stabilization. A pump brightness of 110 MW.cm-2sr-1 has been obtained with a linewidth lower than 80 pm at 798 nm. This laser source has been used to pump a Nd:ASL crystal to obtain 300 mW at 906 nm and 53 mW at 453 nm by intracavity doubling with a LBO crystal

900 nm Emission of a Nd:ASL Laser Pumped by an Extended-Cavity Tapered Laser Diode

PosterWe describe here the use of a 798-nm-stabilized high-brightness tapered laser diode to pump a Nd:ASL crystal for 900 nm laser operation. An output power of 150 mW is obtained

Diode-pumped Pr:BaY2F8 cw orange laser

We report the realization of the continuous wave laser emission in the orange at 607 nm from a Pr:BaY2F8 (Pr:BYF) crystal pumped by a blue GaN laser diode. A maximal output power of 78 mW is obtained in a quasi single transverse mode beam. The effect of reabsorption losses at the laser wavelength is also evidencedComment: accepted for publication in Optics Letter

Combinaison cohérente de diodes laser de luminance élevée en cavité externe

The constant and growing demand for compact and efficient laser sources leads to explore new architectures aiming at increasing the output powers of laser diodes. The most promising solution consists in utilizing several moderate-power identical lasers in parallel. It is then necessary to induce a constant phase relationship between the lasers to maintain the spatial beam quality. We present a theoretical and experimental study of the passive phase locking of an array of high-power diode lasers. We take benefit of the angular and spectral filtering properties of volume Bragg gratings in an external cavity. Two solutions have been considered: the first one uses the self-imaging Talbot effect and the second one consists in a selective angular filtering of the array emission. A theoretical model aiming at determining the modal behavior of those two cavities has been realized. Moreover, concerning the Talbot cavity, in collaboration with the University of Nottingham, a cavity model taking into account the internal properties of the diode lasers has also been used. Experimentally, several cavity setups adapted to different array geometries have been investigated. Each of them achieved a coherent emission. We show that the use of volume Bragg gratings inside the cavity improve both the coherence and the spectrum of the lasers. Finally, we present an original solution using phase filters to convert the multilobed beam from the laser cavity into a Gaussian beam profile.La demande en constante progression de sources laser compactes et efficaces conduit à rechercher des architectures nouvelles pour accroître la puissance des diodes laser. La solution la plus prometteuse consiste à utiliser plusieurs lasers identiques de puissance modérée en parallèle. Pour conserver la qualité spatiale du faisceau, il est nécessaire d'induire une relation de phase constante entre les lasers. Nous présentons une étude théorique et expérimentale de la mise en phase passive d'une barrette de diodes laser de puissance. Pour cela, nous exploitons les propriétés de filtrage angulaire et spectral des réseaux de Bragg volumiques dans une cavité externe. Deux solutions ont été étudiées : la première exploite l'effet d'auto-imagerie Talbot et la seconde effectue un filtrage sélectif des composantes angulaires de l'émission de la barrette. Un modèle théorique permettant de déterminer le comportement modal de chacune de ces cavités a été réalisé. Dans le cas de la cavité Talbot, en collaboration avec l'Université de Nottingham, la cavité a également été modélisée en prenant en compte les propriétés internes des diodes laser. Expérimentalement, plusieurs architectures adaptées à des géométries de barrettes différentes ont été étudiées, qui ont toutes donné lieu à une émission cohérente. Nous montrons que l'utilisation d'un réseau de Bragg volumique intra-cavité permet à la fois d'améliorer la cohérence entre les lasers et de stabiliser le spectre d'émission. Enfin, nous présentons une solution originale utilisant des filtres de phase permettant de convertir le faisceau cohérent multilobe provenant de la cavité laser en un faisceau de profil gaussien

Theoretical and experimental evaluation of a wavelength-stabilized Talbot cavity with a volume Bragg grating

We describe the coherent combining and the wavelength stabilization of 10 tapered lasers in an external Talbot cavity. The use of a volume Bragg grating as feedback element to narrow the spectrum is demonstrated

Passive coherent combining of diode lasers in external cavity configurations

International audienceCoherent combining of diode lasers results in the addition of their laser powers while maintaining their high spatial and spectral brightness. Passive external-cavity configurations are described, using the self-imaging Talbot effect and Dammann gratings

Modal conversion of a phase-locked extended-cavity diode laser array into a single lobe

International audiencePhase-locked operation of an array of ten diode lasers is demonstrated in an extended-cavity using the Talbot self-imaging effect. An output power up to 1.7 W has been obtained. The extracavity coherent conversion of the multilobed array supermode into a Gaussian mode is investigated theoretically based on a binary phase grating. The best configuration results in a conversion efficiency of 83%. Experimentally, the conversion efficiency reaches 50% and is limited by the imperfect coherence of the laser array. We conclude that the conversion setup provides an actual measurement of the power in the selected array supermode