Diode-pumped passively mode-locked Nd:KGd(WO(4))(2) laser with 1-W average output power

Femtosecond Alexandrite laser passively mode-locked by an InP/InGaP quantum-dot saturable absorber

An Alexandrite laser passively mode-locked using an InP/InGaP quantum-dot semiconductor saturable absorber mirror (QD-SESAM) was demonstrated. The laser was pumped at 532 nm and generated pulses as short as 380 fs at 775 nm with an average output power of 295 mW. To the best of our knowledge, this is the first report on a passively mode-locked femtosecond Alexandrite laser using a SESAM in general and a QD-SESAM in particular.

Discretely selectable multiwavelength operation of a semiconductor saturable absorber mirror mode-locked Nd:YVO4 laser

We report on a semiconductor saturable absorber mirror mode-locked Nd:YVO₄ laser operating at discretely selectable 1064.0, 1073.0, 1085.1 nm wavelengths with the average output powers of more than 2.2 W at each of the three wavelengths. The optical-to-optical efficiencies and the slope efficiencies were larger than 19% and 29% for each of the three wavelengths, and the pulse durations at the highest output powers were 13.1, 10.3, and 8.4 ps, respectively.

Diode-pumped Nd:YVO4 laser with discrete multi-wavelength tunability and high efficiency

Selectable and discretely tunable multi-wavelength diode-pumped Nd:YVO₄ laser operating at 1064.0, 1073.1, and 1085.2 nm was demonstrated using a single intracavity birefringent plate. Under 11.2 W of absorbed pump power, the maximum output power of more than 3.8 W for any of the three wavelengths was achieved with slope and optical-to-optical efficiencies of more than 45% and 35%, respectively.

Multiwatt continuous wave Nd:KGW laser with hot-band diode pumping

We have demonstrated what we believe is the first continuous wave neodymium-doped potassium gadolinium tungstate crystal (Nd:KGW) laser with hot-band diode pumping at ∼910  nm. This pumping wavelength reduced the quantum defect by >46% as compared to conventional ∼810  nm pumping and resulted in significantly lower thermal lensing. The laser produced 2.9 W of average output power at 1067 nm in a diffraction-limited beam for an absorbed pump power of 8.3 W. The slope efficiency and optical-to-optical efficiency were found to be 43% and 35%, respectively. Significant reduction of quantum defect offered by this pumping wavelength and availability of suitable high-power laser diodes opens up an attractive way to further power and efficiency scaling of Nd:KGW lasers.

34.7 μJ, <10 ps, Megahertz-level laser output based on a cavity-dumped mode-locked Nd:GdVO₄ oscillator

We report on a high-power passively mode-locked, cavity-dumped picosecond oscillator with dual Nd:GdVO₄ crystal schemes. An average power of up to 19 W is obtained at 8.1 MHz, corresponding to a pulse energy of 2.35 μJ in continuous-wave mode-locking. With electro-optic cavity dumping, pulse energies of 16.22 μJ at 1 MHz and 34.7 μJ at 300 kHz are achieved, with pulse widths of 8.55 and 7.0 ps, respectively. These results demonstrate the potential of Nd:GdVO₄ as a very promising candidate for high-power ultrafast laser.

Enhanced efficiency of Er:Yb:Ce:NaGd(WO4)2 laser at 1.5-1.6 microm by the introduction of high-doping Ce3+ ions

By the introduction of high-doping Ce3+ ions, the upconversion fluorescence of Er3+ ions was reduced, and the energy-transfer efficiency from Yb3+ to Er3+ ions was enhanced significantly in Er:Yb:Ce:NaGd(WO4)2 crystals. End pumped by a diode laser at 970 nm in a hemispherical cavity, a 2.0 W quasi-cw laser at 1.5-1.6 microm with slope efficiency of 19% and absorbed pump threshold of 2.0 W was achieved in a 1.7-mm-thick c-cut Er:Yb:Ce:NaGd(WO4)2 crystal. The results show that the Er.:Yb:Ce:NaGd(WO4)2 crystal with high-doping Ce3+ ions is a potential gain medium for a low-threshold 1.5-1.6 microm laser.

Efficient Raman shifting of high-energy picosecond pulses into the eye-safe 1.5-microm spectral region by use of a KGd(WO4)2 crystal

We report an efficient transient stimulated Raman conversion of high-energy picosecond pulses at 1350 nm into the eye-safe 1500-nm wavelength range by use of a KGd(WO4)2 crystal. The conversion efficiency into either 1503- or 1537-nm radiation (767- or 901-cm(-1) Raman modes, respectively) is measured to be approximately 10% in a single-pass configuration. The transient Raman gain coefficient is found to be approximately 0.8 cm/GW. Simultaneous generation of multiple Raman lines is also observed.

Passive mode locking of a diode-end-pumped Nd:GdVO4 laser with a semiconductor saturable absorber mirror

We report an end-pumped and passive mode-locking all-solid-state laser. The laser consists of a Nd:GdVO4 crystal and a linear resonator with a semiconductor saturable absorber mirror that yield mode locking. We achieved stable continuous-wave mode locking with an 8-ps pulse duration at a 154-MHz repetition rate. The average output power was 600 mW with 4 W of pump power. To our knowledge this is the first report of the use of a Nd:GdVO4 crystal for mode locking with a semiconductor saturable absorber mirror.

Diode-pumped passively mode-locked multiwatt Nd:GdVO4 laser with a saturable Bragg reflector

We report a first demonstration, to our knowledge, of a cw passively mode-locked Nd:GdVO4 laser (k = 1063 nm). A relaxed saturable Bragg reflector was used. The laser generates pulses of 9.2 ps at a repetition rate of 119 MHz. As much as 5.4 W of average power was realized with a slope efficiency of 25.7%.