Diode-pumped passively mode-locked Yb:LSO/SESAM laser

Diode-end-pumped passively mode-locked Yb³⁺:Lu₂SiO₅ (Yb:LSO) lasers both in the picosecond and the femtosecond regimes were demonstrated in this paper. The mode-locked lasers were initiated by using of semiconductor saturable absorber mirrors (SESAM). In the absence of intra-prisms for pulse compression, the laser emitted 1.6 W of output power with pulses width of about 4.3 ps. A pair of SF10 prisms was inserted into the laser cavity, pulses as short as 699 fs was generated around a center wavelength of 1043.6 nm with an average output power of 800 mW and a peak power of 11.0 kW.     

Ultrafast laser performance of Yb3 +: Sc2SiO5 crystal with a single-walled carbon nanotube absorber

Single-walled carbon nanotube (SWCNT) absorber fabricated by vertical evaporation is used in passively mode-locked Yb^3 +:Sc₂SiO₅ (Yb:SSO) ultrafast laser for the first time. The performance of Yb:SSO ultrafast laser with pulse width as short as 880 fs is studied and the average output power is 712 mW. To our knowledge, this is the highest output power of femtosecond lasers with SWCNT-SAs reported. In addition, we firstly demonstrate a passively mode-locked picosecond Yb:SSO laser without inserting any dispersion compensation device. The pulses width is as short as 5.4 ps and the output power is 940 mW.     

Spectroscopy and femtosecond laser performance of Yb3+ :Gd0.64Y0.36VO4 crystal

We report for the first time on the efficient continuous-wave and mode-locked laser operation of a diode-pumped Yb:Gd_0.64Y_0.36VO₄ laser. cw output power of 855 mW with a slope efficiency of 45% with respect to the absorbed pump power was demonstrated for the 2.1%-doped crystal. In mode-locked regime with SESAM as passive shutter pulses as short as 100 fs were obtained. PACS 42.55.Xi; 42.65.Re; 42.70.Hj     

High-power 200 fs Kerr-lens mode-locked Yb:YAG thin-disk oscillator

We demonstrate a power-scalable Kerr-lens mode-locked Yb:YAG thin-disk oscillator. It delivers 200 fs pulses at an average power of 17 W and a repetition rate of 40 MHz. At an increased (180 W) pump power level, the laser produces 270 fs 1.1 μJ pulses at an average power of 45 W (optical-to-optical efficiency of 25%). Semiconductor-saturable-absorber-mirror-assisted Kerr-lens mode locking (KLM) and pure KLM with a hard aperture show similar performance. To our knowledge, these are the shortest pulses achieved from a mode-locked Yb:YAG disk oscillator and this is the first demonstration of a Kerr-lens mode-locked thin-disk laser.     

Thermal analysis and efficient high power continuous-wave and?mode-locked thin disk laser operation of Yb-doped sesquioxides

We report on thermal conductivity analysis and thin disk laser power scaling of Yb:Lu₂O₃, Yb:Sc₂O₃, and Yb:LuScO₃. Using a volume Bragg-grating stabilized pump diode we have obtained cw output powers up to 301?W with optical-to-optical efficiencies of up to 73%. In mode-locked operation of an Yb:Lu₂O₃ thin disk laser 141?W of average output power with 738 fs pulses and an optical-to-optical efficiency of 40% were achieved.     

Diode-pumped 65 fs Kerr-lens mode-locked Yb(3+):Lu(2)O(3) and nondoped Y(2)O(3) combined ceramic laser

Diode-pumped Kerr-lens mode-locked laser operation of Yb(3+):Lu(2)O(3) and nondoped Y(2)O(3) combined ceramics has been achieved; 65 fs pulses with an average power of 320 mW under 5 W of pump power were obtained at the center wavelength of 1032 nm. The spectral bandwidth and the time bandwidth product were 18.9 and 0.345 nm, respectively. To our knowledge, this is the first demonstration of a Kerr-lens mode-locked laser operation based on Yb(3+):Lu(2)O(3) ceramic.     

Diode-pumped sub-100 fs Kerr-lens mode-locked Yb3+:Sc2O3 ceramic laser

Diode-pumped Kerr-lens mode-locked laser operations of Yb3+:Sc2O3 ceramics have been achieved. 92 fs pulses with the average power of 850 mW under 3.89 W incident pump power were obtained at a center wavelength of 1042 nm. The optical-to-optical efficiency was 21.9%. 90 fs pulses with the average power of 160 mW were also obtained at a center wavelength of 1092 nm. To our knowledge, this is the first demonstration of a Kerr-lens mode-locked Yb3+:Sc2O3 laser.     

47-fs diode-pumped Yb3+:CaGdAlO4 laser

The experimental demonstration of a diode-pumped passively mode-locked femtosecond laser based on an Yb3+:CaGdAlO4 single crystal is reported. The oscillator is directly diode pumped by a high-brightness 5 W fiber coupled laser diode, and pulses are produced by use of a semiconductor saturable-absorber mirror. It permits the production of pulses as short as 47 fs at 1050 nm, which are to our knowledge the shortest laser pulses obtained from an oscillator based on Yb3+-doped bulk materials. The average power is 38 mW, and the repetition rate is 109 MHz.     

Diode-pumped femtosecond Yb:CaNb2O6 laser

We report to our knowledge a diode-pumped passively mode-locked Yb:CaNb(2)O(6) (Yb:CN) laser for the first time. Both CW and passive mode-locking operation of the laser are experimentally investigated. A maximum CW output power of 1.4 W with a slope efficiency of 20% is obtained on a 7 mm long 1.5 at.% Yb:CN crystal, while stable passive mode-locking with a commercial semiconductor saturable absorption mirror (SESAM) was achieved on a 3 mm long 3 at.% Yb:CN crystal. The mode-locked pulses have pulse width of 251 fs and an average output power of 44 mW at 1038 nm.     

Efficient diode-pumped Yb3+:Y2SiO5 and Yb3+:Lu2SiO5 high-power femtosecond laser operation

We report the mode-locked operation of two new Yb-doped oxyorthosilicates, Y2SiO5 (YSO) and Lu2SiO5 (LSO), that are longitudinally diode pumped. Yb:YSO supplied pulses as short as 122 fs with 410 mW of output power at 1041 nm. More than 2.6 W of average output power, for pulse durations of 198 fs at 1044 nm and 260 fs at 1059 nm for Yb:YSO and Yb:LSO, respectively, were provided. These are, to our best knowledge, the highest values ever obtained and the most efficient mode-locked laser in such a classic fiber-coupled diode-pumping configuration.     

Diode-pumped Yb:Sr(3)Y(BO(3))(3) femtosecond laser

We have developed a diode-pumped Yb(3+)Sr(3)Y(BO(3))(3) (Yb:BOYS) laser generating 69-fs pulses, at a central wavelength of 1062 nm. This laser is mode locked by use of a semiconductor saturable-absorber mirror and emits 80 mW of average power at 113 MHz. This is, to our knowledge, the first mode-locked Yb:BOYS laser and the shortest duration obtained from an ytterbium laser with a crystalline host. The central wavelength can be tuned from 1051 to 1070 nm, for sub-100-fs pulses. We have also achieved an average power as high as 300 mW with pulse duration of 86 fs at 1068 nm.     

High-power diode-pumped passively mode-locked Yb:YAG lasers

We obtained 74-kW peak power and 3.5-W average output power in 1-ps pulses from a diode-pumped Yb:YAG laser at 1030 nm that was passively mode locked with a semiconductor saturable-absorber mirror. Another laser produced 57-kW peak power and as much as 8.1-W average output power in 2.2-ps pulses, split into two nearly diffraction-limited beams (M(2)<1.2) . To our knowledge, these are by far the highest reported peak and average output powers from a diode-pumped mode-locked laser in this pulse-duration regime.     

被动谐波锁模Er3+/Yb3+共掺双包层光纤环形腔激光器

 为了实现高重复频率和高功率的光脉冲,实验采用Er³⁺/Yb³⁺共掺双包层光纤作为增益介质,稳定的中心波长为976 nm的高功率半导体激光器作为泵浦源,利用非线性偏振旋转锁模技术,得到稳定的自起振锁模光脉冲。当泵浦功率为2.4 W时,激光器输出重复频率为8.829 MHz的连续锁模光脉冲,平均输出功率为52.5 mW,自起振锁模泵浦阈值功率为0.6 W,并观测到了稳定的高阶谐波锁模、调Q和调Q-锁模光脉冲输出。     

Spectroscopy and femtosecond laser performance of Yb3+:YAlO3 crystal

We report what we believe to be the first demonstration of cw and passively mode-locked Yb(3+):YAlO(3) (Yb:YAP) laser operation under diode pumping. Spectroscopic properties of a 0.6 at.%Yb(3+)-doped YAP single crystal were investigated. Output power up to 1.2 W with slope efficiency of 64.5% in the cw regime and 225 fs pulse duration with average power of 0.8 W from a mode-locked Yb:YAP laser were demonstrated.     

Diode-pumped femtosecond Yb:KGd(WO(4))(2) laser with 1.1-W average power

We demonstrate what is to our knowledge the first mode-locked Yb:KGd(WO(4))(2) laser. Using a semiconductor saturable-absorber mirror for passive mode locking, we obtain pulses of 176-fs duration with an average power of 1.1 W and a peak power of 64 kW at a center wavelength of 1037 nm. We achieve pulses as short as 112 fs at a lower output power. The laser is based on a standard delta cavity and pumped by two high-brightness laser diodes, making the whole system very simple and compact. Tuning the laser by means of a knife-edge results in mode-locked pulses within a wavelength range from 1032 to 1054 nm. In cw operation, we achieve output powers as high as 1.3 W.     

Diode-pumped Kerr-lens mode-locked femtosecond Yb:YAG ceramic laser

We experimentally demonstrated a diode-pumped Kerr-lens mode-locked femtosecond laser based on an Yb:YAG ceramic. Stable laser pulses with 97-fs duration, 2.8-nJ pulse energy, and 320-mW average power were obtained. The femtosecond oscillator operated at a central wavelength of 1049 nm and a repetition rate of 115 MHz. To the best of our knowledge, this is the first demonstration of a Kerr-lens mode-locked operation in a diode-pumped Yb:YAG ceramic laser with sub-100 fs pulse duration.     

Femtosecond and continuous-wave laser performance of a diode-pumped Yb3+:CaYAlO4 laser

The cw and femtosecond laser operations of Yb(3+):CaYAlO(4) (Yb:CYA) are demonstrated. The laser emitted a maximum cw power of 1.94 W with a slope efficiency (η(slope)) of 71% and an optical-to-optical efficiency (η(opt)) of 51%. Under mode-locking operation, the laser emitted near transform-limited pulses with 156 fs pulse width, 8.1 nJ pulse energy and 0.74 W average power. The η(slope) and η(opt) of the mode-locked laser were 37% and 20%, respectively.     

Efficient and tunable diode-pumped femtosecond Yb:glass lasers

Diode-pumped Yb:phosphate and Yb:silicate glass lasers have been passively mode locked for the first time to the authors' knowledge. Reliable self-starting mode locking without critical cavity alignment has been achieved with intracavity semiconductor saturable-absorber mirrors and soliton mode locking. We generated pulses as short as 58 fs with the Yb:phosphate laser and 61 fs with the Yb:silicate laser at average output powers of 65 and 53 mW, respectively. The pulse repetition rate was 112 MHz. Additionally, we demonstrated tunability of femtosecond pulses from 1025 to 1065 nm for the Yb:phosphate and from 1030 to 1082 nm for the Yb:silicate glasses. The highest mode-locked output power was 405 mW, with 183-fs pulses from the phosphate glass. The diode pump power was 1.68 W, corresponding to 24% optical-to-optical efficiency. The highest cw output power was 510 mW at the same incident pump power.     

Direct amplification of ultrashort pulses in μ-pulling-down Yb:YAG single crystal fibers

We demonstrated that Yb:YAG single crystal fibers have a strong potential for the amplification of femtosecond pulses. Seeded by 230?fs pulses with an average power of 400?mW at 30?MHz delivered by a passively mode-locked Yb:KYW oscillator, the system produced 330?fs pulses with an average power of 12?W. This is the shortest pulse duration ever produced by an Yb:YAG amplifier. The gain in the single crystal fiber reached a value as high as 30 in a simple double-pass configuration.     

Fabrication of aligned single wall carbon nanotube absorbers for high power passive mode-locked Nd:GdVO<Subscript>4</Subscript> laser

Using the vertical evaporation technique we fabricated saturable absorbers by transferring the water-soluble single wall carbon nanotubes (SWCNT) onto a hydrophilic quartz substrate. The fast recovery times of the absorber were measured to be 136 and 790 fs. The modulation depth of the absorber was about 2%. Passive mode-locked Nd:GdVO₄ laser using such an absorber was demonstrated. The continuous wave mode-locked pulses with the pulse duration of 12.4 ps and the repetition of 120 MHz were achieved. The maximum average output power of the mode-locked laser is 2.4 W at the pump power of 13 W. Such kind of absorber has potential to be put into practical use for high power solid-state laser mode locking.