Saturated gain spectrum of VECSELs determined by transient measurement of lasing onset

We describe time-resolved measurements of the evolution of the spectrum of radiation emitted by an optically-pumped continuous-wave InGaAs-GaAs quantum well laser, recorded as lasing builds up from noise to steady state. We extract a fitting parameter corresponding to the gain dispersion of the parabolic spectrum equal to ?79 ± 30 fs2 and ?36 ± 6 fs2 for a resonant and anti-resonant structure, respectively. Furthermore the recorded evolution of the spectrum allows for the calculation of an effective FWHM gain bandwidth for each structure, of 11 nm and 18 nm, respectively

High power femtosecond source based on passively mode-locked 1055nm VECSEL and Yb-fibre power amplifier

We report 5 ns pulses at 160 W average power and 910 repetition rate from a passively mode-locked VECSEL source seeding an Yb-doped fibre power amplifier. The amplified pulses were compressed to 291 fs duration

175 GHz, 400-fs-pulse harmonically mode-locked surface emitting semiconductor laser

We report a harmonically mode-locked vertical external cavity surface emitting laser (VECSEL) producing 400 fs pulses at a repetition frequency of 175 GHz with an average output power of 300 mW. Harmonic mode-locking was established using a 300 µm thick intracavity single crystal diamond heat spreader in thermal contact with the front surface of the gain sample using liquid capillary bonding. The repetition frequency was set by the diamond microcavity and stable harmonic mode locking was achieved when the laser cavity length was tuned so that the laser operated on the 117th harmonic of the fundamental cavity. When an etalon placed intracavity next to the gain sample, but not in thermal contact was used pulse groups were observed. These contained 300 fs pulses with a spacing of 5.9 ps. We conclude that to achieve stable harmonic mode locking at repetition frequencies in the 100s of GHz range in a VECSEL there is a threshold pulse energy above which harmonic mode locking is achieved and below which groups of pulses are observed

First laser operation of an epitaxially grown Tm:Y₂SiO₅ waveguide

With Ti:Sapphire pumping, using a 2% output coupler, a threshold of 62mW and a slope efficiency of 14% was achieved at 1885nm in a Tm:Y2SiO5 waveguide laser grown by Liquid Phase Epitaxy

Fabrication and optical properties of lead-germanate glasses and a new class of optical fibres doped with Tm³⁺

In this article we present a study of a new class of optical fibers based on lead germanate glass. The maximum vibrational frequency of this glass is intermediate between silica and zirconium barium lanthanum aluminum fluoride glass, causing a beneficial change in nonradiative decay and therefore quantum efficiency for particular laser transitions. Fabrication of high-strength, low-loss fibers of this glass has been achieved by modification of the composition to produce optimal physical properties for fiber drawing, while retaining the useful vibrational properties of the original PbGeO2 glass. Measurements of both the thermal and optical properties are described. The fibers produced are ideal for many applications in fiber devices

Growth and low-threshold laser oscillation of an epitaxially grown Nd:YAG waveguide

We report 1064-µm laser operation of an epitaxially grown Nd:YAG planar waveguide with thresholds as low as ~0.7 mW when high-reflectivity mirrors are used. The output is single mode and, when a 83% reflectivity output coupler is used. has a diode pumped slope efficiency of ~40% Output powers in excess of 60 mW have been obtained when pumping with a Rhodamine 6G dye laser

Ion-implanted Nd:GGG channel waveguide laser

We report what is to our knowledge the first fabrication and laser operation of ion-implanted Nd:GGG channel waveguides. Diode-pumped operation has been achieved with absorbed power thresholds as low as ~2 mW and a slope efficiency of ~30% with respect to absorbed power