Stephane Calvez |
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Laboratoire d’Analyse et d’Architecture des Systèmes (LAAS)
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PHOTO Group - Photonics
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Publications (106) View all
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Article: Electrically-controlled rapid femtosecond pulse duration switching and continuous picosecond pulse duration tuning in an ultrafast Cr<sup>4+</sup>:forsterite laser.
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ABSTRACT: We demonstrate rapid switching between picosecond and femtosecond operational regimes in a Cr<sup>4+</sup>:forsterite laser, using an electrically-contacted GaInNAs SESAM with saturable absorption characteristics controlled via the quantum-confined Stark effect. Additionally, continuous picosecond pulse duration tuning by over a factor 3 is reported.Optics Express 07/2012; 20(16):18138-44. · 3.59 Impact Factor -
Article: Thermal lensing, thermal management and transverse mode control in microchip VECSELs
A.J. Kemp, A.J. Maclean, J.E. Hastie, S.A. Smith, J.-M. Hopkins, S. Calvez, G.J. Valentine, M.D. Dawson, D. Burns[show abstract] [hide abstract]
ABSTRACT: Finite-element analysis is used to explore the practicalities and power-scaling potential of quasi-monolithic microchip vertical-external-cavity surface-emitting lasers: thermal lensing and its implications for transverse mode control are emphasised. A comparison is made between the use of sapphire and diamond heat spreaders. The experimental characterisation of an InGaAs/sapphire microchip VECSEL is presented as an exemplar system and the factors affecting slope efficiency, threshold and output power roll-over are examined. By comparing experimental measurements with the finite-element model, the key role of thermal lensing in transverse mode control is demonstrated.Applied Physics B 04/2012; 83(2):189-194. · 2.19 Impact Factor -
Article: Diamond Raman Waveguide Lasers: Completely Analytical Design Optimization Incorporating Scattering Losses
L.J. McKnight, M.D. Dawson, S. Calvez[show abstract] [hide abstract]
ABSTRACT: We report detailed investigation of diamond-on-silica waveguides and their potential for use as Raman lasers. Large cross-sectional area rib waveguides are proposed as a dimension-scalable geometry. Finite element analysis and the beam propagation method are used to assess their guiding properties and in particular single transverse mode operation. A fully analytical model of scattering losses taking into account the interaction with all surfaces is proposed and exploited in conjunction with an analytical solution of a Raman waveguide laser to optimize the design with respect to threshold or output power of a diamond Raman waveguide laser pumped continuous-wave either at 532 nm or 1064 nm. Results show that thresholds lower than 500 mW and near quantum limit output powers can be obtained for a range of guide dimensions.IEEE Journal of Quantum Electronics 09/2011; · 1.88 Impact Factor -
Conference Proceeding: 650MHz-prf-femtosecond Cr4+:Forsterite laser with dispersion-compensating GaInNAs SESAM
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ABSTRACT: We report the use of a near-resonant GalnNAs SESAM in a Cr<sup>4+</sup>:forsterite laser to generate transform-limited 150fs pulses around 1300nm at a repetition-rate of 0.65GHz with average powers up to 270mW.Lasers and Electro-Optics (CLEO), 2011 Conference on; 06/2011 -
Article: Broadly tunable femtosecond mode-locking in a Tm:KYW laser near 2 μm.
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ABSTRACT: Efficient mode-locking in a Tm:KY(WO(4))(2) laser is demonstrated by using InGaAsSb quantum-well SESAMs. Self-starting ultrashort pulse generation was realized in the 1979-2074 nm spectral region. Maximum average output power up to 411 mW was produced around 1986 nm with the corresponding pulse duration and repetition rate of 549 fs and 105 MHz respectively. Optimised pulse durations of 386 fs were produced with an average power of 235 mW at 2029 nm.Optics Express 05/2011; 19(10):9995-10000. · 3.59 Impact Factor