High-power diode-pumped Q-switched and mode-locked Nd:YVO(4) laser with a Cr(4+):YAG saturable absorber

We demonstrate a high-power passively Q -switched and mode-locked Nd:YVO(4) laser with a Cr(4+):YAG saturable absorber. 2.7 W of average power with an 18-kHz Q -switched repetition rate was generated at a 12.5-W pump power. The peak power of a single pulse near the maximum of the Q -switched envelope was greater than 100 kW.     

High-power diode-pumped nonlinear mirror mode-locked Nd:YVO4 laser with periodically-poled KTP

We demonstrate a high-power nonlinear mirror (NLM) mode-locked Nd:YVO₄ laser with a periodically poled KTP (PPKTP). With a 10-mm-long PPKTP crystal, 5.6 W of average power with 20-ps of pulse duration was generated at 18-W of pump power. Compared with conventional type-II KTP crystal with the same length, the stability against the Q-switched mode-locking (QML) is significantly increased with PPKTP in NLM laser; and the pulse duration was also considerably reduced. Received: 21 July 2000 / Revised version: 30 August 2000 / Published online: 10 January 2001     

High-power diode-pumped Q-switched intracavity frequency-doubled Nd:YVO4 laser with a sandwich-type resonator

A compact and efficient diode-pumped acousto-optically Q -switched intracavity frequency-doubled Nd:Y VO(4)/KTP green laser is demonstrated. With 0.5-at. % Nd:Y VO(4), greater than 4.6 W of 532-nm average power at a repetition rate of 50 kHz was generated with 17-W pump power, corresponding to a conversion efficiency of 27%. At 10-30 kHz the pulse width is shorter than 10 ns, and the peak power is higher than 13 kW.     

High-power diode-pumped actively Q-switched Nd:YVO4 self-Raman laser: influence of dopant concentration

Efficient self-Raman frequency conversion from a diode-pumped actively Q-switched Nd:YVO4 laser at 1064 nm to Stokes emission at 1176 nm is achieved for the first time to the author's knowledge. With a 0.2-at.% Nd:YVO4 crystal, greater than 1.5 W of power at a wavelength of 1176 nm at a repetition rate of 20 kHz was generated with a diode pump power of 10.8 W, corresponding to a conversion of 13.9%. Pulse width and peak power were 18 ns and 4.2 kW, respectively.     

Additive-pulse mode locking of a diode-pumped Nd3+:YVO4 laser

We demonstrate self-starting additive-pulse mode locking of a diode-pumped Nd³⁺:YVO₄ laser. Pulse durations of 2.7 ps are measured at a repetition frequency of 90.7 MHz and at an average output power of 1.1 W. This corresponds to a peak power of 4.5 kW. Received: 27 June 2001 / Revised version: 10 October 2001 / Published online: 29 November 2001     

Multi-wavelength diode-pumped Nd:LGGG picosecond laser

Laser operation near 1.06 μm by a diode-pumped Nd:(Lu _x Gd_1?x )₃Ga₅O₁₂ (Nd:LGGG) disordered crystal has been investigated. Cw oscillation, with a slope efficiency as high as 61% and 230 mW output power, was achieved with 400 mW absorbed power from a 1-W laser diode. Stable passive mode locking with single- or multi-banded spectrum was obtained with a semiconductor saturable absorber mirror (SAM) and a single-prism, dispersion-compensated cavity. Fourier limited pulses with duration ≈3–9 ps and output power ≈40 mW were generated at three well-defined laser transitions in the range 1062–1067 nm.     

High-power eye-safe KTA-OPO driven by YVO4/Nd:YVO4 composite laser

We present a high-power 1.53 μm laser based on intracavity KTA-OPO driven by diode-end-pumped acousto-optical Q-switched YVO₄/Nd:YVO₄ composite. The composite crystal was utilized for reducing the thermal effect, and the mode mismatch compensating OPO cavity was designed for efficient OPO conversion. The output power of eye-safe laser at 1535 nm was up to 4.4 W with the pump power of 27 W, corresponding to a diode-to-signal conversion efficiency of 16.3%. To our knowledge, this is the highest output power in diode-end-pumped circumstances. In the experiment, the strong yellow light generated by Raman conversion and frequency doubling in the KTA crystal was observed.     

Phase conjugation in a continuous-wave diode-pumped Nd:YVO4 laser

We demonstrate phase conjugation and dynamic holography by degenerate four-wave mixing in a continuous-wave diode-pumped Nd:YVO₄ laser for the first time. A phase-conjugate reflectivity of 1.4% is obtained with a 12 W diode power. The experimental results and the optimizing parameters, such as the cavity mirror reflectivities, are compared with results from a steady-state theoretical analysis. Received: 6 April 1999 / Published online: 24 June 1999     

A high-average-power diode-pumped Nd:YVO4 regenerative laser amplifier for picosecond-pulses

A 5.3 W average output power at a pulse repetition-rate of 40 kHz was achieved with a diode-end-pumped Nd:YVO₄ regenerative amplifier. In a continuous-wave operation an optical efficiency of 43% was reached. The output pulse duration is 19 ps, if seeded by a 7-ps-oscillator. A maximum pulse repetition-rate of 80 kHz and a maximum pulse energy of 350 J were generated by the entire laser system. PACS 42.65.Re; 42.79.Kr; 42.79.Hp     

Efficient subnanosecond diode-pumped passively Q-switched Nd:YVO4 self-stimulated Raman laser

Generation of efficient subnanosecond self-stimulated Raman pulses by a diode-pumped passively Q-switched Nd:YVO4/Cr4+:YAG laser is demonstrated. Experimental results reveal that self-frequency Raman conversion can be achieved with a c-cut Nd:YVO4 crystal in a nearly hemispherical cavity. At 2.0 W of incident pump power, the self-stimulated Raman laser produces stable 710-ps pulses at a Stokes wavelength of 1178.6 nm with 7.2 microJ of pulse energy at a 17-kHz repetition rate.     

High-power diode-pumped continuous-wave Nd(3+) lasers at wavelengths near 1.44 microm

We demonstrate longitudinally diode-pumped operation of Nd:YAG and Nd:YAP lasers at the long-wavelength end of the (4)F(3/2) ? (4)I(13/2) transition in the eye-safe spectral region at 1444 and 1430 nm, respectively. Special crystal coatings were required for achievement of lasing at these wavelengths. Output powers of up to 4.9 and 2.2 W, with slope efficiencies of up to 22% and 8%, respectively, were achieved. Polarized operation of the Nd:YAG laser yielded output powers of 76% as compared with unpolarized operation. Because of thermal stress, both YAG and YAP crystals were fractured at roughly 25 W of absorbed longitudinal pump power.     

High-power efficient diode-pumped Nd:YVO4/LiB3O5 457 nm blue laser with 4.6 W of output power

Continuous-wave 457 blue laser emission at powers as high as 4.6 W is achieved by using a fiber-coupled laser diode array with a power of 30 W to pump 0.1 at. % low-doped bulk Nd:YVO4 crystal, with intracavity frequency doubling in a 15 mm long type I critical phase-matched LiB3O5 (LBO) crystal in a compact three-fold cavity with a length of less than 100 mm. The optical-optical conversion efficiency is greater than 15.3%, and the stability of the output power is better than 3% for an hour.     

二极管泵浦1064nm单频Nd:YVO4激光器的研究

报道了一种用国产激光二极管泵浦的1064nm单频NdYVO4红外激光器的设计.利用布氏片和石英晶体组合构成的双折射滤光片技术,在泵浦功率为800mW时,实现了功率为360mW的1064nm红外单频输出.测量结果表明,偏振比超过了10001,功率稳定性优于0.5%,振幅噪声小于0.1%.     

Q-switched mode-locked diode-pumped Nd:YVO4 laser with a saturable Bragg reflector

We demonstrated a diode-pumped passively Q-switched mode-locked Nd:YVO4 laser by using a relaxed saturable Bragg reflector (SBR). Stable mode-locked pulse train with the repetition rate of ～230 MHz was achieved and the pulse train was modulated by the Q-switched envelope with the repetition rate of ～150 kHz. The maximum output of 4 W was obtained under the pump power of 13.5 W. The optical-to-optical efficiency was 30%. We also discussed the transition of each process having emerged.     

Compact efficient diode-pumped Nd:YVO4 Q-switched blue laser with intracavity frequency tripling

We demonstrate a compact efficient diode-pumped acousto-optically Q-switched intracavity-frequency-tripled Nd:YVO₄ blue laser. The optimum polarization state is experimentally investigated to optimize the output performance. Greater than 280 mW of 447-nm average power at a repetition rate of 25 kHz was generated with a 15-W diode pump power. At 25 kHz, the pulse width is shorter than 15 ns and the peak power is higher than 800 W.     

Modulation and the linewidth enhancement factor of a diode-pumped Nd:YVO4 laser

A technique based on an FM/AM method is proposed for measuring the linewidth enhancement factor a of a diode-pumped Nd:YVO4 laser. A standard rate equation model is complemented with temperature effects to explain the observed behavior under pump modulation. The result alpha = 0.25 +/- 0.13 agrees with values deduced from recent optical injection experiments.     

High-power diode-end-pumped Nd:YVO4 laser: thermally induced fracture versus pump-wavelength sensitivity

We report two kinds of compact and efficient diode-end-pumped TEM₀₀ lasers with output power >25 W at ≈50 W of incident pump power. One laser consists of a single 0.3 at. % Nd:YVO₄ crystal in a V-type cavity, the other laser includes two 0.5 at. % Nd:YVO₄ crystals in a linear cavity. Experimental results show that lowering Nd³⁺ concentration can be beneficial in extending the fracture-limited pump power but it also increases the sensitivity of the pump wavelength due to the overlapping efficiency. Received: 19 February 2000 / Revised version: 30 May 2000 / Published online: 20 September 2000     

High-power air-cooled SiC-clad Nd:YVO4 slab lasers

We demonstrate a diode-pumped, air-cooled, 100 W class SiC-clad Nd:YVO(4) active slab laser based on diffusion bonding of two SiC plates to a thin Nd:YVO(4) slab. We obtained 83 W of cw output power with a slope efficiency of 27% without water cooling. This demonstration initiates a novel (to the best of our knowledge) cooling design for efficient removal of waste heat generated from the diode edge-pumped high-power slab laser at room temperature.     

New green self-frequency-doubling diode-pumped Nd:Ca4GdO(BO3)3 laser

3+ :Ca₄GdO(BO₃)₃ (Nd:GdCOB). 21 mW of green cw laser emission for an absorbed pump power of 820 mW were achieved under laser diode-pumping. 64 mW of green cw laser output were obtained with 1 W of absorbed pump power under titanium-sapphire pumping. Its availability in large-size crystals with good optical quality makes Nd:GdCOB a true challenger to the best SFD laser crystal reported so far: Nd:YAl₃(BO₃)₄ (Nd:YAB or NYAB). Received: 2 March 1998/Revised version: 20 May 1998     

激光二极管抽运Nd∶YVO4和KTP倍频产生单频绿光激发器

报道了一种激光二极管抽运、KTP倍频的Nd∶YVO4激光器,采用折叠腔,实现了稳定的高输出单频倍频运转,绿光输出功率达到102 mW,转换效率为10.7 %.