Green Er(3+):YLiF(4) upconversion laser at 551nm with Yb(3+) codoping: a novel pumping scheme

We report room-temperature continuous-wave upconversion laser emission on the green transition (4)S(3/2)?(4)I(15/2) in Er(1%), Yb(3%):YLiF(4) at 551nm. Green laser operation was obtained for titanium-sapphire pump wavelengths continuously tunable between 955 and 974.5nm. Codoping with Yb(3+) resulted in a more efficient excitation of the upper laser level by upconversion processes. The maximum green laser output power was 37mW at an incident titanium-sapphire pump power level of 1580mW at 966nm.     

Passive mode locking of a self-frequency-doubling Yb:YAl(3) (BO(3))(4) laser

We report passive mode-locking experiments with a novel self-doubling laser crystal Yb:YAl(3)(BO(3))(4) (Yb:YAB). The diode-pumped laser was mode locked by an ion-implanted semiconductor saturable absorber mirror. Far off phase matching, soliton mode locking produced pulse widths of 198 fs to 1.4 ps, with up to 660-mW output and optical efficiency of 24% at 1040 nm. The shortest pulses had a peak power of 28 kW with 440-mW average power and 16% efficiency. A few degrees off phase matching, a total of 60 mW of green femtosecond pulses was generated simultaneously. Close to phase matching, the laser produced picosecond pulses and, without infrared output, a total of 270 mW of green output, corresponding to 10% conversion efficiency (absorbed pump to green output).     

A High Efficiency Yb~(3 )-doped Fiber Ring Cavity Laser with Narrow Line-width

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Performance of a low-loss pulsed-laser-deposited Nd:Gd(3) Ga(5)O(12) waveguide laser at 1.06 and 0.94 mum

We report the laser performance of a low-propagation-loss neodymium-doped Gd(3)Ga(5)O(12) (Nd:GGG) waveguide fabricated by pulsed-laser deposition. An 8- mum -thick crystalline Nd:GGG film grown upon an undoped Y(3)Al(5)O(12) substrate lases at 1.060 and 1.062 microm when pumped by a Ti:sapphire laser operating at 740 or 808nm.Using a 2.2% output coupler, we observed a 1060-nm laser threshold of 4mW and a slope efficiency of 20%. Laser action was also achieved, for what we believe is the first time in Nd:GGG, on the quasi-three-level 937-nm transition. With a 2% output coupler at this wavelength a laser threshold of 17mW and a 20% slope efficiency were obtained. This demonstration of low propagation loss combined with the fact that these waveguides have a very high numerical aperture (0.75) makes pulsed-laser-deposited thin films attractive for high-power diode-pumped devices.     

Efficient continuous-wave self-frequency-doubling green diode-pumped Yb:YAl(3)(BO(3))(4) lasers

Efficient cw self-frequency-doubled green laser output of 160 mW has been obtained from Yb:YAl(3)(BO(3))(4) crystal pumped by 1.4-W incident power from a fiber-coupled 976-nm laser diode. The incident-pump-power-green-output-power conversion efficiency is greater than 11.3%, and the electrical-input-green conversion efficiency is 3.9%. Tunable green output from 513.0 to 545.8 nm is also demonstrated with a quartz birefringent filter.     

Passively Q-switched microchip Er, Yb:YAl3(BO3)4 diode-pumped laser

We report, for the first time to our knowledge, a diode-pumped cw and passively Q-switched microchip Er, Yb:YAl(3)(BO(3))(4) laser. A maximal output power of 800 mW at 1602 nm in the cw regime was obtained at an absorbed pump power of 7.7 W. By using Co(2+):MgAl(2)O(4) as a saturable absorber, a TEM(00)-mode Q-switched average output power of 315 mW was demonstrated at 1522 nm, with pulse duration of 5 ns and pulse energy of 5.25 μJ at a repetition rate of 60 kHz.     

Studies on the SFD Properties of Nd_xGd_(1-x)Ca_4O(BO_3)_3 Solid-solution Crystal

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｉｎｔｈｅｐａｓｔｆｅｗｙｅａｒｓ,ｓｍａｌｌｓｉｚｅｄＳＦＤｌａｓｅｒｈａｓａｔｔｒａｃｔｅｄｇｒｅａｔａｔｔｅｎｔｉｏｎｓ.Ｌａｓｅｒｄｉｏｄｅ(ＬＤ)ｐｕｍｐｅｄｓｏｌｉｄｓｔａｔｅｌａｓｅｒｓｈａｖｅｂｅｅｎｆｏｕｎｄｖｅｒｙｕｓｅｆｕｌｉｎｔｈｅｆｉｅｌｄｓｏｆｍｉｌｉｔａｒｙ,ｉｎｄｕｓｔｒｙ,ｍｅｄｉｃａｌｔｒｅａｔｍｅｎｔａｎｄｓｃｉｅｎｔｉｆｉｃｒｅｓｅａｒｃｈｅｓｄｕｅｔｏｔｈｅａｄｖａｎｔａｇｅｓｏｆｈｉｇｈｓｔａｂｉｌｉｔｙ,ｃｏｍｐａｃｔｎｅｓｓ…     

Growth and laser properties of Nd:Ca4YO(BO3)3 crystal

Nd:Ca₄YO(BO₃)₃ (Nd:YCOB) crystal was grown by the Czochralski method, and its structure was measured by using a four circle X-ray diffractometer. The transparent spectrum from 200 to 2600 nm was measured at room temperature. The fluorescence spectrum near 1.06 μm showed that the main emission wavelength of Nd:YCOB crystal was centered at 1060.8 nm. Laser output at 1.06 μm has been demonstrated when it was pumped by a Ti:sapphire laser at the wavelength of 794 nm, the highest output power was 68 mW under pumping power of 311 mW, the pumping threshold was 163 mW and slope efficiency was 46.9%. The self-frequency doubled green light has been observed when it was pumped by a Ti:sapphire or a laser diode (LD). A 14.5 mm Nd:YCOB crystal sample cut at (θ, φ)=(90°, 33°) was used for type I second-frequency generation (SHG) of the 1.06 μm laser pulse. The SHG conversion efficiency was 22%.     

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.     

Ultralow-threshold Kerr-lens mode-locked Ti:Al(2)O(3) laser

An ultralow-threshold Kerr-lens mode-locked Ti:Al(2)O(3) laser achieved by use of an extended cavity design is demonstrated. Mode-locking thresholds as low as 156 mW are achieved. Pulses with durations as short as 14 fs and bandwidths of >100 nm with output powers of ~15 mW at 50-MHz repetition rates are generated by only 200 mW of pump power. Reducing the pump power requirements to a factor of 10x less than required by most conventional Kerr-lens mode-locked lasers permits inexpensive, low-power pump lasers to be used. This will facilitate the development of low-cost, high-performance femtosecond Ti:Al(2)O(3) laser technology.     

An all-fiber type Er~(3+)/Yb~(3+) co-doped fiber laser

In this paper, a distributed Bragg reflection (DBR) type Er~(3+)/Yb~(3+) co-doped fiber laser of high output power and high slope efficiency was developed. Its gain medium was a 4.45-m-long Er3+/Yb3+ co-doped fiber. When it was pumped by a 1064-nm Nd:YAG, the linewidth of output laser was measured as 0.072 nm by 3 dB and 0.192 nm by 25 dB at 1552.08 nm. The maximum output power was measured as 69 mW. Its power stability was < 5%, side mode suppression ratio was 59 dB, and the output wavelength stability was ±0.01 nm. The laser had a threshold of 12 mW and a slope efficiency of 22%.     

Continuous wave and tunable laser operation of Yb3+ in disordered NaLa(MoO4)2

Continuous-wave Yb³⁺ laser operation is studied in single crystals of disordered NaLa(MoO₄)₂ at room temperature. The sample used was grown by the Czochralski technique and incorporates an Yb ion density of 3.1×10²⁰ cm^-3. The effect of the Yb concentration on some of the crystal properties is described as well as the spectroscopic Yb³⁺ properties at 5 K. Maximum slope efficiencies of about 40% for π and 38% for σ polarization were obtained under Ti:sapphire laser pumping near 976 nm, respectively. The maximum output power for the π polarization was 400 mW at 1039.5 nm, the threshold in this case amounted to 240 mW (absorbed pump power). The laser emission was tunable between 1016 and 1064 nm with a Lyot filter. Lasing was also realized by pumping with a fiber-coupled diode laser module. Maximum output power of 900 mW at 1035 nm was achieved in this case for the π polarization and the threshold was 280 mW. The results, in terms of output power and tunability, are superior in comparison to all previous reports on Yb-doped disordered double tungstate or molybdate crystals and represent a significant improvement in comparison to earlier experiments with low-doped Yb:NaLa(MoO₄)₂.PACS 42.55.Rz; 42.55.Xi; 42.70.Hj     

Diode-pumped continuous-wave Nd<Superscript>3+</Superscript>:YAlO<Subscript>3</Subscript> intracavity-doubled red laser

It is reported that efficient continuous-wave (CW) red laser generation at 670 nm in a LBO crystal at type-I phase matching direction performed with a diode-pumped Nd³⁺:YAlO₃ (Nd:YAP) laser. With incident pump power of 15.6 W, output power of 273 mW at 670 nm has been obtained using a 10 mm-long LBO crystal. At the output power level of 273 mW, the output stability is better than 3.7%.     

Studies on the SFD Properties of NdxGd1-xCa4O(BO3)3 Solid-solution Crystal

NdxGd1-xCa4O(BO3)3 (NdGdCOB) is a new self-frequency-doubling (SFD) solid-solution crystal. The second-harmonic generation (SHG) phase-matching (PM) curves were calculated by using refractive indices. The deff of NdGdCOB crystal along different PM directions were calculated according to the sellmeier equation and dijk data in which the (θ=66.8°, φ=132.6°) PM direction has the highest deff. SFD experiments were carried out with Ti:sapphire CW laser and pulsed dye-laser. A green laser output power up to 225 mW at 530 nm was achieved from a 7×3×3 mm3 crystal sample pumped by 1560 mW CW Ti:sapphire laser. The lasing threshold of SFD was lower than 1.8 mW along the PM direction (66.8°,132.6°). The optical-optical conversion efficiency was 14.4%. The conversion efficiency was 7.7% when 10×3×3 mm3 sample was side-pumped by the pulsed dye-laser tuned to 595.4 nm with 17.5 mJ energy and the lasing threshold is 1.2 mJ.     

Continuous-wave room-temperature laser oscillation of Cr(3+):MgO

Continuous-wave laser oscillation of Cr(3+):MgO at room temperature was realized under argon-ion laser pumping at 476 and 514 nm. The free-running laser wavelength was 840 nm, and with different mirror sets laser oscillation at 824, 830, 870, and 878 nm was also realized. With different crystals a maximum output power of 48 mW and a lowest threshold with respect to the absorbed pump power of 80 mW were realized. The slope efficiencies with respect to the absorbed pump power were as high as 2.3%. No thermal effects were observed for absorbed pump powers as great as 2.7 W.     

(Tm,Ho):YLF微片激光器的实验研究

报道了一台连续792 nm Ti:Al2O3激光器纵向抽运的(Tm,Ho):YLF微片激光器.在室温条件下,当抽运功率为680 mW时,激光器在2.06 μm波长的输出功率达到90 mW.激光器阈值为380 mW,光光转换效率为13%,斜率效率为26%.     

High-average-power light source below 200 nm from a KBe(2)BO(3)F(2) prism-coupled device

Using a 2.3 mm thick KBe(2)BO(3)F(2) crystal optically contacted with CaF(2) in a prism-coupled device, we have obtained an average output power of as much as 360 mW at 200 nm. Long-term stability was verified above a 150 mW level at 200 nm. An output power of 50 mW was also obtained with a narrow spectral width of 0.007 pm at 193.5 nm.     

504 nm blue-green laser based on sum-frequency mixing of diode pumped Nd<Superscript>3+</Superscript> lasers

We report for the first time a continuous-wave (CW) blue-green radiation at 504 nm by intracavity sum-frequency generation of 946 nm Nd:YAG laser and 1080 nm Nd:YAlO₃ (Nd:YAP) laser. Using type-I critical phase matching LiB₃O₅ (LBO) crystal, 504 nm blue-green laser was obtained by 946 and 1080 nm intra-cavity sum-frequency mixing, and output power of 215 mW was demonstrated. At the output power level of 215 mW, the output power stability is better than 4.7% and laser beam quality M² factor is 1.21.     

Laser diode-array pumped Nd:YAlO_3 CW laser at 1079.5nm and 1341.4nm

Two key problems,spectral matching and spatial overlap between pumpingbeam and the laser mode in the active material,of diode-laser-arrays(LD)end-pumped solid-state laser have been discussed.Initial experimental results were given for LD end-pumpedTEM_(00) CW Nd:YAlO_3 laser at the wavelength of 1079.5nm and 1341.4nm.The outputpower at 1079.5nm is 24.4mW with 14.5％ slope efficiency,and the output power is 1.2mW at 1341.4nm.     

Power scaling of laser diode pumped Pr3+:LiYF4 cw lasers: efficient laser operation at 522.6 nm, 545.9 nm, 607.2 nm, and 639.5 nm

We report efficient cw laser operation of laser diode pumped Pr(3+)-doped LiYF4 crystals in the visible spectral region. Using two InGaN laser diodes emitting at λ(P)=443.9?nm with maximum output power of 1?W each and a 2.9-mm-long crystal with a doping concentration of 0.5%, output powers of 938?mW, 418?mW, 384?mW, and 773?mW were achieved for the laser wavelengths 639.5?nm, 607.2?nm, 545.9?nm, and 522.6?nm, respectively. The maximum absorbed pump powers were approximately 1.5?W, resulting in slope efficiencies of 63.6%, 32.0%, 52.1%, and 61.5%, as well as electro-optical efficiencies of 9.4%, 4.2%, 3.8%, and 7.7%, respectively. Within these experiments, laser diode-pumped laser action at 545.9?nm was demonstrated for what is believed to be the first time.