高效率,窄脉冲1198.5nm Ba(NO_3)_2喇曼激光器(英文)

利用1 064 nm的Nd∶YAG激光抽运振荡腔内的硝酸钡晶体,获得高效率、窄脉冲的喇曼激光输出.硝酸钡晶体由水溶液降温法生长,长度为48 mm.喇曼振荡腔由对抽运光、一阶、二阶斯托克斯光有不同反射率的双色平面镜构成.当抽运光功率达到4.5 W时,获得最高的一阶斯托克斯喇曼激光功率为1.48 W,相应的转换效率为32.9%,并测得斜率效率为40%.由于受激喇曼散射的作用,喇曼脉冲光由抽运脉冲光的19.8 ns压缩为2.4 ns,获得的喇曼激光脉冲波形具有的＂上升沿陡峭、下降沿缓慢＂的特性,对其形成过程作了

Radially polarized and pulsed output from passively Q-switched Nd:YAG ceramic microchip laser

For the first time, to the best of our knowledge, a radially polarized laser pulse was produced from a passively Q-switched Nd:YAG ceramic microchip laser with a piece of Cr4+:YAG crystal as the saturable absorber and multilayer concentric subwavelength grating as the polarization-selective output coupler. The averaged laser power reached 450 mW with a slope efficiency of 30.2%. The laser pulse had a maximum peak power of 759 W, a minimum pulse duration of 86 ns, and a 6.7 kHz repetition rate at 3.7 W absorbed pump power. The polarization degree of the radially polarized pulse was measured to be as high as 97.4%. Such a radially polarized laser pulse with a high peak power and a short width is important to numerous applications such as metal cutting. (C) 2008 Optical Society of America

Passively Q-switched Yb : YAG laser with Cr4+: YAG as the saturable absorber

By using a continuous-wave Ti:sapphire laser as a pumping source, we demonstrated a passively Q-switched Yb:YAG laser at room temperature with Cr4+:YAG as the saturable absorber. We achieved an average output power of as much as 55 mW at 1.03 mum with a pulse width (FWHM) as short as 350 ns. The initial transmission of the Cr4+:YAG has an effect on the pulse duration (FWHM) and the repetition rate of the Yb:YAG passively Q-switched laser. The Yb:YAG crystal can be a most promising passively Q-switched laser crystal for compact, efficient, solid-state lasers. (C) 2001 Optical Society of America.

Laser-diode-pumped Cr4+,Nd3+: YAG with self-Q-switched laser output of 1.4 W

By use of a laser diode as a pump source, a self-Q-switched laser from a Cr,Nd:YAG crystal is demonstrated. The output Q-switched traces are very stable, the threshold pump power is 3.5 W, the pulse duration is 50 ns, and the slope efficiency is as high as 20%. In addition, the pulse width remains constant while the pulse repetition rate Varies with pump power. (C) 2000 Optical Society of America OCIS codes: 140.0140, 140.2020, 140.3380, 140.3480, 140.3540, 140.3580.

Three-dimensional micro- and nano-fabrication in transparent materials by femtosecond laser

Femtosecond pulsed lasers have been widely used for materials microprocessing. Due to their ultrashort pulse width and ultrahigh light intensity, the process is generally characterized by the nonthermal diffusion process. We observed various induced microstructures such as refractive-index-changed structures, color center defects, microvoids and microcracks in transparent materials (e.g., glasses after the femtosecond laser irradiation), and discussed the possible applications of the microstructures in the fabrication of various micro optical devices [e.g., optical waveguides, microgratings, microlenses, fiber attenuators, and three-dimensional (3D) optical memory]. In this paper, we review our recent research developments on single femtosecond-laser-induced nanostructures. We introduce the space-selective valence state manipulation of active ions, precipitation and control of metal nanoparticles and light polarization-dependent permanent nanostructures, and discuss the mechanisms and possible applications of the observed phenomena.

Room-temperature cw and pulsed operation of a diode-end-pumped Tm:YAP laser

We report the continuous-wave and acousto-optical Q-switched operation of a diode-end-pumped Tm:YAP laser. Continuous-wave output power of 3.5 W at 1.99 mu m was obtained under the absorbed pump power of 14 W. Under Q-switched laser operation, the average output power increased from 1.57 W to 2.0 W, with an absorbed pump power of 12.6 W, as the repetition rate increased from 1 kHz to 10 kHz. The maximum Q-switched pulse energy was 1.57 mJ with a repetition rate of 1 kHz. The minimum pulse width was measured to be about 80 ns, corresponding to a peak power of 19.6 kW.

Diode-pumped Q-switched Tm:YAP laser with a pump recycling scheme

We reported on a diode end-pumped AO Q-switched Tm:YAP laser at 1937 nm. The average output power was 3.9 W, with a slope efficiency of 29.4% and optical-optical conversion efficiency of 21.6% at a 5-kHz repetition rate. The temperature dependency of the output power and the pulse width at different repetition rates were investigated in details.

Room temperature efficient actively Q-switched Ho:YAP laser

We report on efficient actively Q-switched Ho: YAP laser double-pass pumped by a 1.91-mu m laser. At room temperature, when the incident pump power was 20.9 W, a maximum average output power of 10.9W at 2118 nm was obtained at the repetition rate of 10 kHz, and this corresponds to a conversion efficiency of 52.2% and a slope efficiency of 63.5%. Moreover, a maximum pulse energy of similar to 1.1 mJ and a minimum pulse width of 31 ns were achieved, with the peak power of 35.5 kW. (C) 2009 Optical Society of America

Investigation of damage threshold to TiO2 coatings at different laser wavelength and pulse duration

Laser-induced damages to TiO2 single layers and TiO2/SiO2 high reflectors at laser wavelength of 1064 nm, 800 run, 532 urn, and pulse width of 12 ns, 220 ps, 50 fs, 8 ns are investigated. All films are prepared by electron beam evaporation. The relations among microstructure, chemical composition, optical properties and laser-induced damage threshold (LIDT), have been researched. The dependence of damage mechanism on laser wavelength and pulse width is discussed. It is found that from 1064 nm to 532 nm, LIDT is mainly absorption related, which is determined by film's extinction coefficient and stoichiometric defects. The rapid decrease of LIDT at 800 nm is due to the pulse width factor. TiO2 coatings are mainly thermally by damaged at long pulse (tau >= 220 ps). The damage shows ablation feature at 50 fs. (C) 2007 Elsevier B.V. All rights reserved.

Diode-pumped passively mode-locked YVO4/Nd : YVO4 composite crystal laser with LT-In0.25Ga0.75As saturable absorber

A passively mode-locked all-solid-state YVO4/Nd:YVO4 composite crystal laser was realized with a low temperature (LT) In0.25Ga0.75As semiconductor saturable absorber mirror. The saturable absorber was used as nonlinear absorber and output coupler simultaneously. Both the Q-switch and continous-wave mode locking operation were experimentally realized. At a pump power of 4 W, the Q-switched mode locking changed to continuous wave mode locking. An average output power of 4.1 W with 5 ps pulse width was achieved at the pump power of 12 W, corresponding to an optical-optical conversion efficiency of 34.2%.

A Diode-Side-Pumped Dynamic Fundamental Mode Nd:YAG Laser

A fundamental mode Nd YAG laser is experimentally demonstrated with a stagger pumped laser module and a special resonator. The rod is pumped symmetrically by staggered bar modules. A dynamic fundamental mode is achieved with the special resonator under different pump levels. A maximal continuous wave output of 61 W (M-2 = 1.4) is achieved with a single rod. An average output of 47 W, pulse width of 54 ns, pulse energy of 4.7 mJ and peak power of 87 kW are obtained under the Q-switched operation of 10 kHz.

Thermal effects investigation and cavity design in passively mode-locked Nd:YVO4 laser with a SESAM

A diode-pumped passively mode-locked Nd YVO4 laser with a five-mirror folded cavity is presented by using a semiconductor saturable absorber mirror (SESAM). The temperature distribution and thermal lensing in laser medium are numerically analyzed to design a special cavity which can keep the power density on SESAM under its damage threshold. Both the Q-switched and continuous-wave mode-locked operation are experimentally realized. The maximum average output power of 8.94 W with a 9.3 ps pulse width at a repetition rate of 111 MHz is obtained under a pump power of 24 W, correspondingly the optical slope efficiency is 39.2%. (C) 2008 Elsevier B.V. All rights reserved.

Passively mode-locked YVO4/Nd:YVO4 composite crystal green laser with a semiconductor saturable absorber mirror

A diode-pumped passively mode-locked YVO4/Nd YVO4 composite crystal green laser with a semiconductor saturable absorber mirror (SESAM) and a intracavity frequency-doubling KTP crystal was realized. The maximum average output power of 2.06 W at 532 nm with a repetition rate of 100 MHz was obtained at a pump power of 15 W, corresponding to optical slop efficiency 17.2%. The 532 nm mode-locked pulse width was estimated to be approximately 18-ps.

Diode-end-pumped passively mode-locked ceramic Nd : YAG Laser with a semiconductor saturable mirror

We report on a diode- pumped CW passively mode locked ceramic Nd: YAG laser with SESAM ( semiconductor saturable absorber mirror), wavelength 1064nm. At a pump power of 7.6w, the pulse width was estimated to be similar to 8.3ps with repetition rate similar to 130MHz and the average output power was 1.59w. To our knowledge, this was the first demonstration that ceramic Nd: YAG was used for diode pumped CW passively mode locking. (C) 2005 Optical Society of America.

Passive mode locking of diode-end-pumped Nd : GdVO4 laser with an In0.25Ga0.75As output coupler

Passive mode locking of a diode-pumped Nd:GdVO4 laser was demonstrated using In0.25Ga0.75As as saturable absorber as well as output coupler. The pulse width was measured to be about 16 ps with a repetition rate of 146 MHz. The average output power was 120 mW with pump power of 6 W. To our knowledge, this is the first demonstration on a passively mode-locked Nd:GdVO4 laser by using an In0.25Ga0.75As output coupler. (C) 2004 Elsevier B.V. All rights reserved.