A 54-fs diode-pumped Kerr-lens mode-locked Yb:LuYSiO_(5) laser

We demonstrate a Kerr-lens mode-locked Yb:Lu YSiO_(5)(Yb:LYSO)laser with the pulse duration of 54 fs,corresponding to a spectral bandwidth of 25 nm centered at 1062 nm.To the best of our knowledge,this is the shortest pulse duration obtained from Yb:LYSO laser.At the repetition rate of 378.3 MHz,an output power of 111.6 m W is obtained using an output coupler with 0.6%transmittance,which can maintain long-time stable mode-locking more than 13 h.

Continuous-Wave and Actively Q-Switched Diode-Pumped Er:LuAG Ring Laser at 1650 nm

We demonstrate a cw and actively Q-switched Er：LuAO laser resonantly dual-end-pumped by 1532nm fibre- coupled laser diodes. A maximum cw output power of 1.9W at 1650.3nm is obtained at a pump power of 25.5 W, corresponding to a slope efficiency of 43.3 %. In the Q-switched regime, the maximum pulse energy of 3.51 mJ is reached at a pulse repetition rate of 100 Hz, a pulse duration of 90.5ns and a pump power of 25.5 W. At the repetition rate of 400 Hz, the output energy is 2.12m J, corresponding to a pulse duration of 125.4 ns.

Diode-Pumped Passively Mode-Locked 1079 nm Nd:CaGdAlO_4 Laser

We demonstrate a diode-pumped passively cw mode-locked Nd：CaGdAlO4 laser operating at 1079nm with a semiconductor saturable absorber mirror for the first time to the best of our knowledge. The threshold pump power of the laser is 180mW. A maximum average output power of 93mW is obtained under the pump power of 1.94 W. The pulse duration of the mode-locked pulses is 3.1ps and the repetition rate is 157MHz.

7.6-W diode-pumped femtosecond Yb:KGW laser

We have demonstrated a high power diode-pumped mode-locked femtosecond Yb:KGW laser with semiconductor saturable absorber mirror(SESAM). By using an output coupler with 10% transmittance, the laser delivered 160-fs pulses with average output power of 7.6 W at a repetition rate of 78 MHz, corresponding to pulse energy of 97 nJ and peak power of 606 kW.

Diode-pumped laser performance of Tm:Sc2SiO5 crystal at 1971 nm

The 4-at.% Tm：Sc_2SiO_5 （Tm：SSO） crystal is successfully obtained by the Czochralski method. The optical properties and thermal conductivity of the crystal are investigated. The broad continuous wave（CW） laser output of（100）-cut Tm：SSO with the dimensions of 3 mm×3 mm×3 mm under laser diode（LD）-pumping is realized. The full width at half maximum（FWHM） of the laser emitting reaches up to 21 nm. The laser threshold of Tm：SSO is measured to be 0.43 W. Efficient diode-pumped CW laser performance of Tm：SSO is demonstrated with a slope efficiency of 25.9% and maximum output power of 934 mW.

Diode-Pumped c-Cut Nd:Lu0.99La0.01VO4 Self-Stimulated Raman Laser at 1181 nm

The self-stimulated Raman laser operation of a Nd：Lu0.99La0.01VO4 new crystal is presented. A 0.3at.% Nd doped Lu0.99La0.01VO4 crystal in dimensions 3 × 3 × 20 mm^3 is adopted as the self-stimulated Raman crystal. At a pulse repetition frequency of 14kHz, average output powers of 24OmW for the first Stokes light at 1181 nm and 660mW for the fundamental light at 1068nm are obtained under an incident pump power of 5.5 W. The pulse widths of the first Stokes light and fundamental light are about 15 and 25us. The slope effieiencies are about 12. 7% and 18.8% with respect to the incident pump power.

Efficient Diode-Pumped Actively Q-Switched Ceramic Nd:YAG/YVO4 Raman Laser Operating at 1657 nm

A diode-pumped actively Q-switched Raman laser is demonstrated, with YV04 employed as Raman active medium, based on a ceramic Nd：YAG laser operating at 1444nm. The first-stokes Raman generation at 1657nm is achieved. A maximum output power of as high as 612mW is obtained under a pump power of 20. 7 W and at a pulse repetition frequency rate of 20kHz, corresponding to an optical-to-optical conversion efficiency of 3%.

Diode-pumped Doubly Q-switched Nd∶YAG Laser with Acoustic-optical Modulator and Cr^(4+)∶YAG Saturable Absorber

A diode-pumped doubly Q-switched Nd∶YAG laser operating at 1064nm both with an acoustic-optical(AO)modulator and Cr4+∶YAG saturable absorber in the cavity is demonstrated.At the incident pump power of 11.8W the laser can generate stable 8ns pulse with the peak power of 23.6kW at a 10kHz repetition rate.The pulse temporal profile is more symmetric and shorter compared with that of passively Q-switched lasers with only AO-active and Cr4+∶YAG.A reasonable analysis is developed to explain the experimental results theoretically.

Temperature-Dependent Fluorescence Properties and Diode-Pumped Deep Red Laser Performance of Pr:LiGdF4 Crystal

We demonstrate the temperature-dependent fluorescence properties of Pr：LiGdF4 crystal tor the first time, to the best of our knowledge, and its blue diode pumped cw red laser at 720 nm at room temperature. The fluorescence lifetime and polarized emission cross sections in the visible range are measured and calculated in a temperature range from 77K to 300 K, and the variations of the fluorescence lifetime and spectra are discovered. The reasons for these changes are explained accordingly. The output wavelength of the 720nm laser is first reported on the laser performance by using a fiber-coupled laser diode at the wavelength of 442nm as the pump source, and the maximum cw output power is about 303roW.

Sub-10-fs pulse generation from a blue laser-diode-pumped Ti:sapphire oscillator

Pulses as short as 8.1 fs were generated from a blue laser-diode-pumped Kerr-lens mode-locked Ti:sapphire oscillator, with an average power of 27 m W and a repetition rate of 120.6 MHz. The full width at half-maximum exceeds 146 nm, benefitting from the dispersion management by a combination of a low-dispersion fused silica prism pair and a series of double-chirped mirrors. To the best of our knowledge, this is the first time to generate sub-10-fs pulses from a laser diode directly pumped Ti:sapphire oscillator.

Pushing the boundaries of diode-pumped solid-state lasers for high-energy applications

We report on the successful demonstration of a 150 J nanosecond pulsed cryogenic gas cooled,diode-pumped multi-slab Yb:YAG laser operating at 1 Hz.To the best of our knowledge,this is the highest energy ever recorded for a diodepumped laser system.

Generation of sub-100-fs pulses from a diode-pumped Yb：Y3ScAl4O12 ceramic laser

We experimentally demonstrate the generation of sub-100-fs pulses from a diode-pumped passively mode-locked Yb：Y3ScAl4O12 （Yb：YSAG） ceramic laser. Stable mode-locked pulses as short as 96 fs at the central wavelength of 1052 nm with a repetition rate of -102 MHz are obtained. The laser has a maximum average output power of 51 mW. To the best of our knowledge, these are so far the shortest pulses and the first demonstration of sub-100- fs pulses obtained from the mode-locked Yb：YSAG ceramic lasers.

High-beam-quality, 5.4 J, 5 Hz diode-pumped Nd:YAG active mirror laser amplifier

A high-beam-quality diode-pumped neodymium-doped yttrium aluminum garnet(Nd:YAG) active mirror laser amplifier was demonstrated. The size of the Nd:YAG crystal was 48 mm × 42 mm × 11 mm with 0.6 at.% Nd doped. When the pump energy was 26.8 J and the input energy was 0.3 J, the output pulse energy reached 5.4 J, and the pulse width of 11.3 ns at a 5 Hz repetition rate was obtained for the two gain modules in three-pass amplification, with corresponding optical-to-optical efficiency of 21.2%. The beam quality was measured as M_x^2=2.48 and M_y^2=2.43 in horizontal and vertical directions, respectively.

Scaling diode-pumped, high energy picosecond lasers to kilowatt average powers

Recent results in the development of diode-driven high energy, high repetition rate, picosecond lasers, including the demonstration of a cryogenic Yb:YAG active mirror amplifier that produces 1.5 J pulses at 500 Hz repetition rate(0.75 kW average power) are reviewed. These pulses are compressed resulting in the generation of ~5 ps duration,1 J pulses with 0.5 kW average power. A full characterization of this high power cryogenic amplifier, including atwavelength interferometry of the active region under >1 kW average power pump conditions, is presented. An initial demonstration of operation at 1 kW average power(1 J, 1 k Hz) is reported.

Power and spectral analyses in diode-pumped c-cut Pbnm Tm:YAP laser

Detailed power and spectral analysis of a diode-pumped c-cut Pbnm 3 at.% Tm-doped yttrium aluminum perovskite(Tm:YAP) laser in a continuous wave(CW) operation is presented. The laser was experimentally examined in terms of the dependence on the transmittance and radius of curvature of the output coupling mirrors.At room temperature, for an output coupling transmission of 10.8%, the maximum output power of 6.35 W was obtained under a total absorbed pump power of 13.67 W with an optical-to-optical conversion efficiency of 46.5%. The highest slope efficiency of 60.4% was indicated. A detailed spectral analysis was presented. For its dependence on output coupler transmission, the Tm:YAP laser generates wavelengths at approximately 1940 nm or 1990 nm.

Thermal lens analysis in a diode-pumped 10 Hz 100 mJ Yb:YAG amplifier

We address the power scaling issue in end-pumped laser rod amplifiers by studying,experimentally and numerically,the magnitude of thermal lensing in a high-energy diode-pumped Yb:YAG crystal.The spatio-temporal temperature profile of the gain medium and the focal length of the induced thermal lens are determined numerically.The influence of the repetition rate and pumping power on the temperature distribution is analyzed.Experimental measurements covered repetition rates between 1 and 10 Hz and up to 4 kW pumping power.

Graphene oxide for diode-pumped Tm:YLF passively Q-switched laser at 2 μm

A diode-pumped Tm：YLF passively Q-switched laser at 2 μm was first demonstrated by using graphene oxide（GO） as a saturable absorber（SA）.In this letter,continuous-wave（CW） laser and pulse laser performances were studied meticulously and systematically.It reasonably showed the dependence of the pulse duration,pulse energy,and pulse repetition rate on the absorbed power.A maximum repetition rate of 38.33 kHz and a single pulse energy of 9.89 μJ were obtained.

High power and beam quality continuous-wave Nd:Gd VO_4 laser in-band diode-pumped at 912 nm

We report on the performance of a continuous-wave Nd:Gd VO_4 laser in-band diode-pumped at 912 nm with high output power and excellent beam quality. The laser produced an output power of 19.8 W at 1063 nm with an optical efficiency of 59.3% and slope efficiency of 62.7%. The laser threshold was ~2.04 W of the absorbed pump power, and the laser output beam quality was ≤ 1.2 in the horizontal and vertical directions. The strength of thermal lensing at full output power(33.4 W of absorbed power) was measured to be an average of 8.6 diopters.It is shown that thermal lensing is reduced by a factor of 2 with respect to the Nd:YVO_4 lasers, thus opening a way for further output-power scaling.

Highly efficient diode-pumped seven-rod resonator with a 3.79-kW output

Thermally stable region of a seven-rod resonator is theoretically investigated. A plane-plane symmetric resonator, where the distance between two neighbor rods is two times of that between the rods and the mirrors, is adopted because of its large stable range. Based on the investigation, a seven-rod resonator with an average output power of 3.79 kW and an optical-to-optical efficiency of 53% is developed.

Quantitative analysis of C, Si, Mn, Ni, Cr and Cu in low-alloy steel under ambient conditions via laser-induced breakdown spectroscopy

A diode-pumped solid-state laser （DPSSL） with a high energetic stability and long service life is applied to ablate the steel samples instead of traditional Nd：YAG laser pumped by a xenon lamp, and several factors, such as laser pulse energy, repetition rate and argon flow rate, that influence laser-induced breakdown spectroscopy （LIBS） analytical performance are investigated in detail. Under the optimal experiment conditions, the relative standard deviations for C, Si, Mn, Ni, Cr and Cu are 3.3%-8.9%, 0.9%-2.8%, 1.2%-4.1%, 1.7%-3.0%, 1.1%-3.4% and 2.5%-8.5%, respectively, with the corresponding relative errors of 1.1%-7.9%, 1.0%-6.3%, 0.4%-3.9%, 1.5%-6.3%, 1.2%-4.0% and 1.2%-6.4%. Compared with the results of the traditional spark discharge optical emission spectrometry technique, the analytical performance of LIBS is just a little inferior due to the less stable laser-induced plasma and smaller amount of ablated sample by the laser. However, the precision, detection limits and accuracy of LIBS obtained in our present work were sufficient to meet the requirements for process analysis. These technical performances of higher stability of output energy and longer service life for DPSSL, in comparison to the Q-switch laser pumped by xeon lamp, qualify it well for the real time online analysis for different industrial applications.