A cw uv copper hollow cathode laser in the 260 nm region

A cw uv copper hollow cathode laser is described, which could be operated for a longer time duration with an output power of 7 mW in the 260 nm region. A double-cathode configuration with a protection for the mirrors from metal-vapour deposition is presented. Characteristics of the laser output power, the spontaneous emission, and the ion densities in the negative glow were measured as depending on the discharge current, the neon gas pressure, and the size of the cathode slit. The observed saturation of the laser output power at high discharge current (1 A/cm²) and the optimum slot size are discussed.     

Highly efficient, low-cost femtosecond Cr3+ :LiCAF laser pumped by single-mode diodes

We describe efficient continuous-wave (cw) and cw mode-locked operations of a Cr3+ :LiCAF laser, pumped by inexpensive single spatial mode laser diodes. Up to 280 mW of cw output power was obtained with 570 mW of absorbed pump power, with a corresponding slope efficiency of 54%. Continuous tuning between 765 and 865 nm was demonstrated using a fused silica prism. A semiconductor saturable absorber mirror was used to initiate and sustain stable, self-starting, mode-locked operation. In cw mode locking, the laser produced 72 fs (FWHM) duration pulses, and 1.4 nJ pulse energy, at an average output power of 178 mW. Electrical to optical conversion efficiencies of 7.8% in mode-locked operation and 12.2% in cw operation were demonstrated.     

Tunable,continuous-wave,ultra-violet radiation around 300 nm by frequency-doubling a rhodamine 6G dye laser

By frequency doubling a cw Rhodamine 6G dye laser using an ADP crystal placed in the laser cavity, in excess of 30 mW of cw uv radiation has been generated. The radiation is tunable over the range 285–315 nm. The ADP crystal is cut with Brewster angle ends, and is located at the focus of cavity compensated for coma and astigmatism. Conversion efficiency is shown to be limited by the onset of thermally induced phase mismatching. Peak uv power can be increased to 85 mW by chopping the radiation from the pumping laser.     

Optimization of the UV CuII laser

The cw output power of the uv CuII laser has been optimized with respect to the hollow cathode geometry, the discharge current, the fill gas pressure and the resonator mirror parameters. A maximum laser output power of 900 mW for multiline operation at 248.6, 259.1, 260.0, and 270.3 nm was achieved with 100 A discharge current, 260 V voltage and 16 mbar fillgas pressure, when a hollow cathode of 1.2 m length and 2×6 mm² cross section was employed. The single-pass pain gl has been estimated to 7%. A hollow cathode cross section of 1.5×4.5 mm² is suggested as an optimum geometry. In addition, some investigations on the mechanism of the laser power decay in Ne–Cu-discharges are presented.     

Diode-pumped, high-average-power femtosecond Cr3+ :LiCAF laser

We demonstrate a high-average-power continuous wave (cw) and cw mode-locked Cr3+ :LiCAF laser pumped by broad-area laser diodes. In cw lasing experiments, up to 580 mW of output was obtained with 4.35 W of incident pump. A semiconductor saturable absorber mirror was used to initiate stable, self-starting, mode locking. In the cw mode-locked regime, the Cr3+ :LiCAF laser produced nearly transform-limited, 67 fs long pulses near 800 nm with an average output power of 300 mW. The pulse repetition rate was 120 MHz, with a pulse energy of 2.5 nJ.     

Diode-pumped cw Nd:YAG three-level laser at 869 nm

We report for the first time (to our knowledge) a diode-pumped Nd:YAG laser emitting at 869 nm based on the (4)F(3/2)-(4)I(9/2) transition, generally used for a 946 nm emission. Power of 453 mW at 869 nm has been achieved in cw operation with a fiber-coupled laser diode emitting 35.4 W at 809 nm. Intracavity second-harmonic generation in the cw mode has also been demonstrated with power of 118 mW at 435 nm by using a BiB(3)O(6) nonlinear crystal. In our experiment, we used a LiNbO(3) crystal lens to complement the thermal lens of the laser rod, and we obtained good beam quality and high output power stability.     

Passively Mode-Locked Quasi-Three-Level Nd:LuVO4Laser with Semiconductor Saturable Absorber Mirror

We demonstrate a passively a Z-folded resonator. Using device, we achieve stable cw average output power under cw mode-locked Nd：LuVO4 laser operating on the quasi-three-level at 916nm with a semiconductor saturable absorber mirror （SESAM） as the passive mode-locking mode locking with 6.7ps pulse duration at repetition rate of 133 MHz and 88mW the pump power of 17.1 W.     

Diode-pumped high-power cw blue laser at 473 nm with a compact three-element cavity

We report on a diode-pumped cw Nd:YAG laser operating at 946 nm with a maximum output power of 3.3 W and a slope efficiency of 22% with respect to the incident pump power of 17.5 W. Intracavity frequency doubling with nonlinear crystal LBO yielded a single-ended blue output power of 590 mW with optical conversion efficiency of 3.4%. A very simple, compact three-element cavity of 35 mm long was used. The power fluctuation of the blue laser was 4.3% (rms) at output power level of 400 mW. Transverse mode hopping was observed at higher output power.     

激光二极管抽运Nd∶YVO4/LBO腔内倍频5.3 W连续波激光器

报道了激光二极管双向抽运Nd∶YVO4 晶体、LBO腔内倍频、最大输出功率为 5 .3W的连续波绿光激光器。采用LBO晶体Ⅰ类非临界相位匹配 (NCPM) ,温度调谐 ,当抽运光功率为 2 0W时 ,获得了 5 .3WTEM0 0 模 5 32nm绿光输出 ,光光转换效率达 2 6 .5 %。并对绿光模式及输出功率随LBO晶体温度的变化关系进行了测量 ,与理论结果符合较好。     

Continuous-wave laser at 440 nm based on frequency-doubled diode-pumped Nd:GdVO(4) crystal

We present for the first time, to the best of our knowledge, a frequency-doubled Nd:GdVO(4) laser operating in a cw on the pure three-level laser line at 880 nm. We obtained 300 mW at 440 nm for 23 W of incident pump power at 808 nm. Moreover, with a 25% output coupler we obtained a cw power of 1.9 W at the fundamental wavelength at 880 nm.     

Theory and experiment of CW dye laser injection locking and its application to second harmonic generation

High-power single-mode operation of a cw ring dye laser has been obtained by injection of cw single-mode radiation. The intracavity power of this system was used to generate tunable single-mode uv radiation by frequency doubling in a temperature phase-matched ADA crystal: up to 45 W intracavity fundamental power and up to 70 mW extracted uv power have been observed. A theoretical treatment of the injection locked cw ring dye laser system is given for the stationary state. Expressions for the intracavity intensities as a function of the small-signal gain and the saturation intensity are derived.     

Diode-pumped Nd:GAGG-LBO laser at 531 nm

We report a green laser at 531 nm generation by intracavity frequency doubling of a continuous wave (cw) laser operation of a 1062 nm Nd:GAGG laser under in-band diode pumping at 808 nm. A LiB₃O₅ (LBO) crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation of the laser. At an incident pump power of 18.5 W, as high as 933 mW of cw output power at 531 nm is achieved. The fluctuation of the green output power was better than 3.5% in the given 4 h.     

Stable High Power and High Beam Quality Diode-Side-Pumped Continuous-Wave Intracavity Frequency-Doubled Nd:YAG Laser

We report a stable high power and high beam quality diode-side-pumped cw green laser from intracavity frequency-doubled Nd： YAG laser with KTP. By using a L-shaped concave-convex resonator, designed with two Nd：YAG rods birefringence compensation, a large fundamental mode size in the laser crystal and a tight focus in the nonlinear crystal could be obtained simultaneously. The green laser delivers a maximum 532nm output power of 23.2 W. Under 532nm output power of 20.9 W, the beam quality factor is measured to be 4.1, and the fluctuation of the output power is less than 1.4% in an hour.     

A Stable Wavelength Operation Ho:YAG Laser with Orthogonally Polarized Pump

A stable wavelength operation Ho:YAG laser dual-pumped by two orthogonally polarized Tm:YLF lasers is reported. Under the cw operation mode, a laser output power of 24 W is measured. The corresponding opticaloptical conversion efficiency is 44.75% and the slope efficiency is 50.12%. Under the Q-switched operation mode,the output maximum average power is 22.8 W at the re-frequency of 6 kHz. The corresponding optical-optical conversion efficiency and slope efficiency are 42.64% and 48.01%, respectively. The output central wavelength is 2090.73 nm, the linewidth is 0.40 nm, and the beam quality is M~2 1.6. Moreover, the shift of the output central wavelength is less than 0.01 nm, and the linewidth shift is also less than 0.01 nm.     

Diode-pumped passively mode-locked Nd:YVO4 laser at 1342 nm with periodically poled LiNbO3

In this Letter, we demonstrate a nonlinear-mirror (NLM) mode-locked diode-pumped solid-state Nd:YVO4 laser operating at 1342?nm, in which the NLM comprises a periodically poled LiNbO3 crystal and a dichroic mirror. The self-starting threshold for cw mode locking is 1.5?W, which is significantly lower than that of saturable absorber mode locking. An average power of 1.52?W at 1342?nm is obtained under diode pump power of 10?W at 808?nm, with the slope efficiency being up to 16.8%. The pulse width and the repetition rate of the mode-locked laser output are about 9.5?ps and 101?MHz, respectively.     

Diode-pumped Nd:LGS/LBO laser at 452 nm

We report a blue laser at 452 nm generation by intracavity frequency doubling of a continuous wave (cw) laser operation of a 904 nm Nd:LGS laser under 808 nm diode pumping. A LiB₃O₅ (LBO) crystal, cut for critical type I phase matching at room temperature is used for second harmonic generation (SHG) of the laser. At an incident pump power of 17.8 W, as high as 1.14 W of cw output power at 452 nm is achieved. The optical-to-optical conversion efficiency is up to 6.4%, and the fluctuation of the blue output power was better than 4.1% in the given 30 min.     

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.     

High Power Photonic Crystal Fibre Raman Laser

A cw Raman laser based on a 100-m photonic crystal fibre is demonstrated with up to 3.8 W output power at the incident pump power of 12 W, corresponding to an optical-to-optical efficiency of about 31.6%.. The second order Stokes light, which is firstly reported in a cw photonic crystal fibre Raman laser, is obtained at 1183nm with an output power of 1.6 W and a slope efficiency of about 45.7%.     

Continuous-wave all-solid-state 244 nm deep-ultraviolet laser source by fourth-harmonic generation of an optically pumped semiconductor laser using CsLiB6O10 in an external resonator

We report an all-solid-state laser system that generates over 200 mW cw at 244 nm. An optically pumped semiconductor laser is internally frequency doubled to 488 nm. The 488 nm output is coupled to an external resonator, where it is converted to 244 nm using a CsLiB(6)O(10) (CLBO) crystal. The output power is limited by the available power at 488 nm, and no noticeable degradation in output power was observed over a period of several hours.     

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

We demonstrate a cw and actively Q-switched Er.LuAG laser resonantly dual-end-pumped by 1532 nm fibrecoupled 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 of3.51 mJ is reached at a pulse repetition rate of 100 Hz,a pulse duration of 90.5 ns and a pump power of 25.5 W.At the repetition rate of 400 Hz,the output energy is 2.12 mJ,corresponding to a pulse duration of 125.4 ns.