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1.
Q-switched microchip laser emitting radiation at eye-safe wavelength 1444 nm was designed and realized. This laser was based
on composite crystal which consists of 4 mm long Nd:YAG active medium diffusion bonded with 1 mm long V:YAG saturable absorber.
The diameter of the composite crystal was 5 mm. The initial transmission of the V:YAG part was T
0 = 94% @ 1440 nm. The microchip resonator consists of dielectric mirrors, directly deposited onto the composite crystal surfaces.
These mirrors were specially designed to ensure desired emission at 1444 nm and to prevent parasitic lasing at other Nd3+ transmissions. The output coupler with reflectivity 94% for the generated wavelength 1444 nm was placed on the V3+-doped part. The laser was operating under pulsed pumping for the duty-cycle up to 50%. With increasing value of mean pumping
power a strong decrease of generated pulse length was observed. The shortest generated pulses were 4.2 ns long (FWHM). Stable
pulses with energy 34 μJ were generated with repetition rate up to 1.5 kHz. Corresponding pulse peak power was 8.2 kW. The
wavelength of linearly polarized TEM00 laser mode was fixed to 1444 nm. 相似文献
2.
In this research we study lasing without population inversion from a three-level atom interacting with two laser fields, in
the ladder or cascade scheme. We investigate counterintuitive sequencing as well as regular sequencing of the time of laser
fields application. In a counterintuitive sequence scheme a short probe pulse is introduced prior to the application of the
coupling field, in contrast, to a standard sequence scheme, where both fields are introduced at the same time. The influence
of varying the probe pulse width and time delay between the initiation of probe and coupling fields on transient probe gain
is investigated. The calculations indicate the potential of producing gain without inversion via counterintuitive sequence
scheme. 相似文献
3.
4.
This paper presents a pulsed Nd: YAG laser-robot system for spot and seam welding of mild steel sheets. The study evaluates the laser beams behaviour for welding, and then investigates pulsed Nd: YAG laser spot and seam welding processes. High pulse power intensity is needed to initiate the key-hole welding process and a threshold pulse energy to reach full penetration. In seam welding, a weld consists of successive overlapping spots. Both high pulse energy and high average power are needed to keep the key-hole welding going. A 70% overlap is used to define overlapping spot welding as seam welding and to optimize process parameters because a high tensile strength joint compatible with the strength of the base material can be obtained when the overlap is ≥70%; at the same time a smooth seam with full penetration is obtained. In these cases, the joints in pulsed Nd: YAG laser welding are comparable in strength to those obtained with CO2 laser welding. Robot positioning and motion accuracies can meet the demands of Nd: YAG laser sheet metal welding, but its cornering accuracy affects the welding processes. The purpose of the study is to evaluate the YAG laser-robot system for production in the automotive industry. 相似文献
5.
Passive mode-locking of a pulsed Nd:YAG laser using a Cr4+:YAG saturable absorber was realized for the first time in a nearly critical stable resonator containing an antiresonant ring structure. The output energy and pulse duration are 13.5 mJ and 180 ps, respectively. The recovery time and saturable intensity for excited-state absorption of Cr4+:YAG under the action of strong laser pulses were calculated from rate equations. 相似文献
6.
The paper describes the microstructure and properties (microhardness and wear resistance) of the bronze laser alloyed with titanium. The laser alloying was done using a pulsed Nd:YAG laser with a generated beam energy of 25-35 J. A very fine microstructure was formed under such rapid solidification conditions like laser treatment. The high chemical homogeneity and fine structure of the melted zone were attributed to high cooling rates due to the short interaction time with Nd:YAG pulsed laser radiation and relatively small volume of the melted material. The structure obtained in the surface layer after laser alloying permits to get a high level of hardness and an improved wear resistance. 相似文献
7.
从LD端面抽运固体激光器的激光阈值公式出发,建立了双波长激光同时振荡的阈值条件,理论计算了腔镜对于两个波长的透过率关系,实现了LD端面抽运Nd:YAG 1319nm/1338nm双波长激光连续和准连续输出.双波长激光连续输出功率可达6W,斜效率为30%;准连续输出功率在重复频率50kHz时可达4.75W,斜效率为24.73%,脉冲宽度为55.05ns;腔内插入布儒斯特片,在重复频率为50kHz时,双波长激光准连续线偏振输出功率可达2.22W,不稳定性小于0.52%,M2
关键词:
端泵Nd:YAG激光器
1319nm/1338nm双波长
声光调Q
太赫兹波 相似文献
8.
Laser-induced breakdown spectroscopy (LIBS) was applied for parametric studies of titanium (Ti) plasma using single and double
pulsed laser excitation scheme. Here a pulsed Nd:YAG laser was employed for generation of laser produced plasma from solid
Ti target at ambient pressure. Several ionized titanium lines were recorded in the 312–334 nm UV region. The temporal evolution
of plasma parameters such as excitation temperature and electron number density was evaluated. The effect of incident laser
irradiance, position of the laser beam focal point with respect to the surface of illumination, single and double laser pulse
effect on plasma parameters were also investigated. This study contributes to a better understanding of the LIBS plasma dynamics
of the double laser pulse effect on the temporal evolution of various Ti emission lines, the detection sensitivity and the
optimal dynamics of plasma for ionized states of Ti. The results demonstrate a faster decay of the continuum and spectral
lines and a shorter plasma life time for the double pulse excitation scheme as compared with single laser pulse excitation.
For double pulse excitation technique, the emissions of Ti lines intensities are enhanced by a factor of five which could
help in the improvement of analytical performance of LIBS technique. In addition, this study proved that to avoid inhomogeneous
effects in the laser produced plasma under high laser intensities, short delay times between the incident laser pulse and
ICCD gate are required. 相似文献
9.
J. Tadano H. Kumakura Y. Ito 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1031-1033
Short and intense laser pulse can process the surface and the inside of transparent materials by focusing the pulse at the desired position. Here we report the interaction of fundamental radiation (1064 nm) of the Q-switched Nd:YAG laser to the surface of PMMA as observed by an imaging system with nanosecond time resolution. The system used fundamental radiation of a Q-switched Nd:YAG laser as a processing laser and second harmonic radiation (532 nm) of another Nd:YAG laser as illuminating light. We observed shock waves which propagate into the material and into the atmosphere by shadowgraph and photoelastic method. Surface roughness of a sample is expected to affect the coupling of light and transparent materials for both normal and focused laser light. Our results have revealed the effects visually. For roughness larger than 0.6 m, all energy is absorbed at the surface, while the larger part of the energy is absorbed inside the material as the surface becomes smoother. PACS 52.38.MF; 79.20.DS; 87.63.Lk 相似文献
10.
从LD端面抽运固体激光器的激光阈值公式出发,建立了双波长激光同时振荡的阈值条件,理论计算了腔镜对于两个波长的透过率关系,实现了LD端面抽运Nd:YAG 1319nm/1338nm双波长激光连续和准连续输出.双波长激光连续输出功率可达6W,斜效率为30%;准连续输出功率在重复频率50kHz时可达4.75W,斜效率为24.73%,脉冲宽度为55.05ns;腔内插入布儒斯特片,在重复频率为50kHz时,双波长激光准连续线偏振输出功率可达2.22W,不稳定性小于0.52%,M2 相似文献
11.
Zhen-Bin Lin Ai-Ping Luo Shi-Ke Wang Hui-Yi Wang Wen-Jun Cao Zhi-Chao Luo Wen-Cheng Xu 《Optics & Laser Technology》2012,44(7):2260-2264
The generation of dual-wavelength domain-wall rectangular-shape pulses in a highly nonlinear fiber (HNLF)-based fiber ring laser is experimentally demonstrated. The dual-wavelength lasing operation is realized by employing the intracavity birefringence-induced spectral filtering effect. An 85 m long HNLF is introduced into the fiber ring laser to enhance the nonlinear effect, which is favorable for the cross coupling between the two lasing beams. Experimentally, it was found that the interval of two domain walls in the time domain could be adjusted by simply tuning the linear cavity phase delay, which results in the achievement of different output pulse shapes. By properly rotating the polarization controller (PC), the dual-wavelength rectangular-shape pulses could be efficiently obtained. The proposed fiber laser provides a simple and efficient way to generate rectangular-shape pulse. 相似文献
12.
A theory of free-electron lasers fed a sequence of short electron pulses is developed. It is assumed that the group velocity
of the electromagnetic pulse that develops in the cavity is the same as the translational velocity of the particles, and the
repetition period of the electron pulses equals the transit time of the electromagnetic radiation in the cavity. Under these
conditions of group synchronism, the principal factors governing the feasibility of establishing a stationary pulsed lasing
regime are found to be the dispersive spread of the electromagnetic pulse and the channeling properties of an electron bunch.
The conditions for self-excitation are found, and the characteristics of the stationary lasing regimes are determined assuming
that the cavity has a high Q and using a parabolic equation for the evolution of the electromagnetic pulse shape.
Zh. Tekh. Fiz. 69, 78–83 (February 1999) 相似文献
13.
We report pulsed laser diode(LD)end-pumped acoustic Q-switched Tm:YAG laser,Tm:LuAG laser,and Tm:LuYAG laser and the physical properties and spectra of Tm:YAG,Tm:LuAG,and Tm:LuYAG are analyzed.The Tm:LuYAG laser is pumped by 785-nm and 788-nm pulses separately,and is compared with Tm:YAG laser.Different output energy values and output wavelengths of Tm:LuAYG lasers pumped by LDs with different wavelengths are obtained and compared with each other.When the repetition frequency is 100 Hz,the pulsed Tm:YAG laser has single pulse energy of 15.9 mJ,pulse width of 126.7 ns,and the center wavelength of 2013.36 nm,and the pulsed Tm:LuAG laser possesses single pulse energy of 11.8 mJ,pulse width of 252.4 ns,and the center wavelength of 2023.65 nm,and the pulsed Tm:LuYAG laser output energy values are 12.32 mJ and 12.25 mJ with the slope efficiencies of 12.5%and 11.85%,the center wavelengths of 2017.89 nm and 2027.11 nm,respectively,while the pump sources are 785-nm and 788-nm pulsed LDs,respectively. 相似文献
14.
The operation of an all solid-state pulsed Nd:KGW Raman laser pumped by compact passively Q-switched Nd:YAG/Cr:YAG laser is
demonstrated. The first-Stokes radiation of stimulated Nd:KGW Raman scattering at the 1178 nm is generated. The average output
power of 336 mW at Stokes wavelength was obtained under the laser diode pump power of 5.74 W. The corresponding optical efficiency
from the diode light to the Raman output is 9.85%. The pulse width of 1.65 ns and a pulse repetition rate of 10 kHz were also
obtained. 相似文献
15.
16.
脉冲激光与碲镉汞相互作用时的冲量耦合 总被引:3,自引:0,他引:3
在激光功率密度为4.0×108~5.0×109Wcm-2的范围内,用冲击摆测量了NdYAG脉冲激光(波长为1.06μm,脉宽为10ns)辐照大气中不同面积的HgCdTe样品时的冲量耦合系数。从理论上建立了等离子体爆轰模型,对激光结束后等离子体的膨胀过程进行了比较详细的描述,用此模型计算了不同能量的脉冲激光与不同面积的HgCdTe相互作用时的冲量耦合系数,计算值与测量值符合得较好。 相似文献
17.
Keenan R Dunn J Patel PK Price DF Smith RF Shlyaptsev VN 《Physical review letters》2005,94(10):103901
We have demonstrated a 10 Hz Ni-like Mo x-ray laser operating at 18.9 nm with 150 mJ total pump energy by employing a novel pumping scheme. The grazing-incidence scheme is described, where a picosecond pulse is incident at a grazing angle to a Mo plasma column produced by a slab target irradiated by a 200 ps laser pulse. This scheme uses refraction of the short pulse at a predetermined electron density to increase absorption to pump a specific gain region. The higher coupling efficiency inherent to this scheme allows a reduction in the pump energy where 70 mJ long pulse energy and 80 mJ short pulse energy are sufficient to produce lasing at a 10 Hz repetition rate. Under these conditions and by optimizing the delay between the pulses, we achieve strong amplification and close to saturation for 4 mm long targets. 相似文献
18.
Cr^4+:YAG在对撞脉冲锁模的Nd:YAG激光器中实现被动锁模的研究 总被引:8,自引:1,他引:7
在理论上提出了Cr^4+:YAG作为可饱和吸收体在Nd:YAG激光器中实现被动锁模的可能性,运用速率方程组导出在强激光脉冲作用下Cr^4+:YAG激发态吸收的恢复时间和饱和光强。实验上在带有抗共振环结构的接近于介稳腔的脉冲式Nd:YAG激光器中用Cr^4+:YAG作为可饱和吸收体实现被动锁模运转,得到能量13.5mJ、平均脉宽180ps的锁模脉冲序列。 相似文献
19.
A copper-vapor laser the lasing medium of which is pumped by damped sine voltage pulses is studied experimentally. It is shown
that this laser can operate at megahertz lasing pulse repetition rates. Each current pulse in a train of damped sine excitation
pulses generates a lasing pulse. The time between lasing pulses is no more than 224 ns, which corresponds to a lasing pulse
repetition rate of more than 4.5 MHz. According to estimates, the use of the megahertz sine voltage to excite the copper-vapor
laser may raise the specific power of laser radiation by at least an order of magnitude at an efficiency of ≈15%. 相似文献
20.
V. F. Lebedev A. P. Pogoda S. N. Smetanin A. S. Boreisho A. V. Fedin 《Technical Physics》2014,59(12):1844-1848
The generation regimes in a pulsed Nd:YAG laser with transverse LED pumping and multiloop self-pumped phase-conjugate cavity on the gain gratings are studied. The differential efficiency of laser is 27% in the free-running regime at a pulse energy of up to 1 J and quality parameter M 2 of no greater than 1.5. The pulse energy under passive Q-switching is no less than 60% of the pulse energy in the free-running regime at the same beam quality. The generation of the narrow-band radiation is demonstrated. A generation band of no greater than 1.2 GHz corresponds to the primary single-frequency high-power laser pulse in the free-running mode under conditions for self-Q-switching on the gain gratings. When additional elements (F 2 ? :LiF and Cr4+:YAG crystals) are introduced in the optical scheme of the phase-conjugate cavity, similar narrowband single-mode generation is observed in the passive Q-switching regime as a pulse train or monopulse. The laser pulse power is up to 2 MW at a pulse duration of 20 ns. 相似文献