1.34 µm VECSEL mode-locked with a GaSb-based SESAM.

Mode locking of a 1.34 µm vertical external cavity surface emitting laser is demonstrated using a GaSb-based semiconductor saturable absorber mirror (SESAM). The SESAM includes six AlGaSb quantum wells (QWs) with an absorption edge at ∼1.37 µm. The proposed approach has two key benefits: the QWs can be grown lattice matched, and only a small number of Bragg reflector layers is required to provide high reflectivity. Pump-probe measurements also reveal that the AlGaSb/GaSb structure exhibits an intrinsically fast absorption recovery on a picosecond timescale. The mode-locked laser pulse train had a fundamental repetition rate of 1.03 GHz, a pulse duration of ∼5 ps, and a peak power of ∼1.67 W. The demonstration paves the way for exploiting GaSb-based SESAMs for mode locking in the 1.3-2 µm wavelength range, which is not sufficiently addressed by GaAs and InP material systems.

Sub-50 ps pulses at 620 nm obtained from frequency doubled 1240 nm diamond Raman laser.

We report a monolithic 1240 nm diamond Raman laser producing pulses with duration of 42-62 ps at 100 kHz repetition rate, and maximum average power of 246 mW. The Raman laser is formed by a 0.5-mm thick planar diamond, coated on both sides and pumped by ~100 ps pulses from a Q-switched 1064 nm laser. The maximum conversion efficiency from 1064 nm to 1240 nm was about 25%. The 1240 nm signal was frequency-doubled in single-pass configuration through a 10-mm long LBO crystal, enabling generation of pulses with a duration of 29-46 ps at 620 nm. The maximum average power at 620 nm was 128 mW, and the maximum conversion efficiency from 1240 nm to 620 nm was 50%. The Raman laser provides an efficient and flexible way to extend short pulse operation to wavelengths in spectral domains difficult to reach, such as 620 nm and in addition provides a simple pulse shortening mechanisms.

Frequency-doubled passively Q-switched microchip laser producing 225 ps pulses at 671 nm.

We report a 671 nm laser source emitting 225 ps pulses with an average power of 55 mW and a repetition rate of 444 kHz. The system consists of a 1342 nm SESAM Q-switched Nd:YVO4 microchip master oscillator and a dual-stage Nd:YVO4 power amplifier. The 1342 nm signal was frequency-doubled to 671 nm using a periodically poled lithium niobate crystal. This laser source provides a practical alternative for applications requiring high energy picosecond pulses, such as time-gated Raman spectroscopy.

2.5 W orange power by frequency conversion from a dual-gain quantum-dot disk laser.

We report a disk laser using two quantum-dot semiconductor gain elements, resulting in what we believe is the first demonstration of intracavity frequency conversion with these active media. Output power of 6 W has been obtained in dual-gain configuration at a wavelength of 1180 nm, while single-gain lasers produced up to 3 and 4 W individually, limited by thermal rollover in the output characteristics. The gain enhancement achieved with two active elements comprising 39 layers of Stranski-Krastanov InGaAs quantum dots allows for intracavity frequency doubling delivering 2.5 W of orange radiation.