Diode-pumped cw and Q-switched Nd:GdVO4 laser operating at 1.34 μm

A diode-pumped 1.34 m Nd:GdVO₄ laser operating in cw and active Q-switching modes has been demonstrated. 4.15 W of cw output power was obtained at the highest attainable pump power of 12.3 W, resulting in an optical conversion efficiency of 33.7%, the slope efficiency was determined to be 37.6%. In Q-switching operation, a maximum average output power of 2.7 W was generated at pulse repetition frequency (PRF) of 50 kHz, with an optical conversion efficiency of 22% and a slope efficiency of 29.2%. The laser pulses with shortest duration, highest energy and peak power were achieved at PRF of 10 kHz, the parameters being 15 ns, 160 J, and 10.7 kW, respectively. By intracavity frequency-doubling with a type II phased-matched KTP crystal, 0.62 W average power at 0.67 m was produced at a PRF of 15 kHz, the resulting pulse energy, peak power, and pulse width being 41.3 J, 2.2 kW, and 19 ns, respectively. A group of analytical formulae, based on rate equations, are presented to evaluate the operational parameters of an actively Q-switched laser. Calculated results were found to be in close consistency with the experimental data.     

Compact and efficient diode-pumped passively Q-switched Nd:GdVO_4 laser at 1.06μm

Diode-pumped passively Q-switched Nd:GdVO4/Cr4+:YAG lasers with a simple flat-flat cavity were demonstrated. The maximum average output power at 1.06 μm was 1.25 W. The highest peak power and pulse energy were 7.56 kW and 75μJ, respectively, with the pulse repetition rate of 11.1 kHz and pulse width of 10 ns at the incident pump power of 8 W.     

Diode-pumped CW Tm:GdVO_4 laser at 1.9 μm

A high power cryogenic cooling Tm-doped (2%) GdVO4 laser double-end-pumped by fiber-coupled-diode with the center wavelength of 804.5 nm at 21 ℃ is reported. The highest continuous-wave (CW) power of 2.35 W at 1903 nm is attained at pump power of 24 W. The slope efficiency is 12.5% and the threshold is 3.2 W. Single- and double-end-pumped types are investigated.     

Diode-pumped passively Q-switched Nd:GdVO4 lasers operating at 1.06 μm wavelength

With a 10-W diode laser to pump Nd:GdVO₄ crystal in a folded cavity, we demonstrated Cr⁴⁺:YAG passively Q-switched Nd:GdVO₄ lasers at 1.06 μm. The maximum average output power of 2.1 W and the highest peak power of 625 W were, respectively, obtained when the initial transmissions of the Cr⁴⁺:YAG crystals were 90% and 80%. Received: 8 September 1999 / Revised version: 30 December 1999 / Published online: 8 March 2000     

Studies on Nd∶YAG Single-pass Amplifiers for High-power Q-switched Laser System

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｉｎｒｅｃｅｎｔｙｅａｒｓ ,ｏｂｖｉｏｕｓｐｒｏｇｒｅｓｓｈａｓｂｅｅｎａｃｈｉｅｖｅｄｉｎｆｌａｓｈｌａｍｐｐｕｍｐｉｎｇＮｄ∶ＹＡＧｌａｓｅｒｓｗｉｔｈｌｏｎｇ ｐｕｌｓｅａｎｄｈｉｇｈａｖｅｒａｇｅｏｕｔｐｕｔｐｏｗｅｒ[1] .ＢｕｔｔｈｅｒｅｅｘｉｓｔｓａｎｅｅｄｆｏｒＱ ｓｗｉｔｃｈｅｄｓｏｌｉｄ ｓｔａｔｅｌａｓｅｒｓｙｓｔｅｍｓｗｉｔｈｈｉｇｈａｖｅｒａｇｅ ｐｏｗｅｒ .ＴｈｉｓｍａｙｂｅａｃｈｉｅｖｅｄｗｉｔｈＮｄ :ＹＡＧｏｓｃｉｌｌａｔｏｒ ａｍｐｌｉｆ…     

Diode-pumped continuous-wave and passively Q-switched 1.06 μm YVO4/Nd:GdVO4 laser

In this letter, a diode-pumped continuous-wave and passively Q-switched 1.06 μm laser with a novel composite YVO₄/Nd:GdVO₄ crystal was demonstrated for the first time. Theoretical calculations showed that the temperature distribution in YVO₄/Nd:GdVO₄ crystal was lower than that in GdVO₄/Nd:GdVO₄ and Nd:GdVO₄ crystals under the same conditions. After optimizing the mode matching degree, a CW output power of 5.6 W of YVO₄/Nd:GdVO₄ laser was obtained at the incident pump power of 12 W when the output coupler with transmission of 30% was employed. Using Cr^4 +:YAG crystals with initial transmission (T₀) of 80% and 90% as saturable absorbers, the pulsed YVO₄/Nd:GdVO₄ laser characteristics were investigated. At the incident pump power of 12 W, the maximum average output power of 2.76 W and the maximum repetition rate of 189 kHz was achieved when T₀ = 90% Cr^4 +:YAG was used. The shortest pulse width was 28.1 ns when the initial transmission of the used Cr^4 +:YAG was 80%.     

Diode-pumped Nd:YGG continuous-wave laser at 1.33 μm

We demonstrated a laser-diode pumped Nd-doped yttrium gallium garnet (Nd:YGG) crystal continuous wave (CW) laser at 1.33 μm for the first time to our knowledge. At an incident pump power of 18.5 W, as high as 3.09 W of CW output power at 1.33 μm is achieved. The slope efficiency with respect to the incident pump power was 21.3%, and the fluctuation of the output power was better than 2.8% in the given 4 h. The beam quality factor M² is 1.14 and 1.16 for tangential direction and sagittal direction, respectively.     

6.5-ns actively Q-switched Nd:YVO_4 laser operating at 1.34 μm

With a plano-concave cavity,diode-pumped continuous-wave(CW) and actively Q-switched Nd:YVO4 laser operating at 1.34 μm is demonstrated.Maximum CW output power of 4.76 W and Q-switched average output power of 2.64 W are obtained with output coupler(transmission T = 3.9%).For the Q-switching operation,the theoretically calculated pulse energy and pulse width,with a pulse repetition frequency(PRF) range of 5-40 kHz,coincide with the experimental results.With a T = 11.9% output coupler,the maximum peak power of 24.3 kW and minimum pulse width of 6.5 ns are obtained when the PRF is 10 kHz.To the best of our knowledge,this is the shortest actively Q-switched pulse duration ever obtained in a 1.3-μm Nd-doped vanadate laser.     

6.5-ns actively Q-switched Nd：YVO4 laser operating at 1.34 μm

A novel design of multimode light power splitter is proposed and fabricated by using secondary asymmetric Y branches.An almost equally divided output among output terminals is obtained experimentally.Maskless laser direct writing technique is applied in the fabrication process to facilitate the formation of power splitters by ultraviolet curable polymer.The analysis of the performances of both four-port and eight-port devices shows that these two dividers obtain a power splitting uniformity of more than 95%.     

Diode-pumped Solid-state Cr~(4 )∶Nd∶YAG/KTP Green Laser

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｄｉｏｄｅ ｐｕｍｐｅｄｓｏｌｉｄ ｓｔａｔｅ ｐａｓｓｉｖｅ Ｑ ｓｗｉｔｃｈｅｄｓｅｃｏｎｄｈａｒｍｏｎｉｃｇｅｎｅｒａｔｉｏｎｌａｓｅｒｈａｓｈｉｇｈｐｏｗｅｒａｎｄｈｉｇｈｒｅｐｅｔｉｔｉｏｎｒａｔｅｐｕｌｓｅｉｎｎａｎｏｓｅｃｏｎｄｐｅｒｉｏｄ ,ａｎｄｖａｒｉｏｕｓａｐｐｌｉｃａｔｉｏｎｓｉｎｍｉｃｒｏ ｍｅｃｈａｎｉｃｓ ,ｍｅａｓｕｒｅｍｅｎｔｓ,ｆｉｌｍ ｃａｒｖｅ ,ｍｉｃｒｏ ｏｐｅｒａｔｉｏｎｓｉｎｓｕｒｇｅｒｙ ,ａｎｄｓｏｏｎ[1] .Ｒｅｃｅｎｔ ｙｅａｒ…     

High-power 1.5 and 3.4 μm intracavity KTA OPO driven by a diode-pumped Q-switched Nd:YAG laser

With a non-critically phase-matched KTA crystal, a high-power intracavity optical parametric oscillator (IOPO) driven by a diode-side-pumped acousto-optically Q-switched Nd:YAG laser has been realized. The maximum average output power of 13.6 W at the signal wavelength of 1534 nm and 3 W at the idler wavelength of 3472.7 nm were obtained with the repetition rate of 18 kHz, giving the optical-optical conversion efficiency of about 5.7% from diode-power at 808 nm to OPO signal output, which was the highest conversion efficiency for intracavity KTA OPO with diode-side-pumping configurations to our best knowledge. At the highest output power of 13.6 W, the signal pulse duration of 5.46 ns was obtained, corresponding to the single pulse energy of 756 μJ and peak power of 138 kW, respectively.     

Diode-pumped vertical external cavity surface emitting laser at 1 μm

We demonstrated a diode-pumped vertical external cavity surface emitting laser with simple plane-concave cavity. When the pump power at a wavelength of 811.6 nm is 1.5 W, the maximum output power is 40.4 mW at the wavelength of 1005.8 nm. The optical-optical conversion efficiency is 2.7%. .     

Over 14 W of CW Radiation at1.06 μm Emitting from a Nd∶GdVO_4 Laser Endpumped by a Diodelaserarray

ＬＩＵＪｕｎｈａｉ　ＳＨＡＯＺｏｎｇｓｈｕ　ＭＥＮＧＸｉａｎｌｉｎ　ＺＨＡＮＧＨｕａｉｊｉｎＺＨＵＬｉ　ＪＩＡＮＧＭｉｎｈｕａ（ＮａｔｉｏｎａｌＬａｂｏｒａｔｏｒｙｏｆＣｒｙｓｔａｌＭａｔｅｒｉａｌｓ,ＳｈａｎｄｏｎｇＵｎｉｖｅｒｓｉｔｙ,Ｊｉｎａｎ２５０１００,Ｃｈｉｎａ）ＲｅｃｅｉｖｅｄＭａｒｃｈ２２,１９９９;ＲｅｖｉｓｅｄｍａｎｕｓｃｒｉｐｔｒｅｃｅｉｖｅｄＭａｒｃｈ２９,１９９９ＤｅｖｅｌｏｐｅｄｂｙＲｕｓｓｉａｎｒｅｓｅａｒｃｈｅｒｓｉｎ１９９２,Ｎｄ∶ＧＤＶＯ４ｉｓａｐｏｔｅｎｔｉ…     

Simultaneous Q-switching and Frequency-doubling by a Single KTP Crystal in a Diode-pumped Nd∶YVO_4 Laser

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｃｏｍｐａｃｔｇｒｅｅｎｌａｓｅｒｓａｒｅｏｆｐｏｔｅｎｔｉａｌｉｎｔｅｒｅｓｔｆｏｒｍａｎｙａｐｐｌｉｃａｔｉｏｎｓ ,ｓｕｃｈａｓｕｎｄｅｒｗａｔｅｒｃｏｍｍｕｎｉｃａｔｉｏｎ ,ｏｐｔｉｃａｌｄａｔａｓｔｏｒａｇｅ,ｄｉｓｐｌａｙ ,ａｎｄｃｈｅｍｉｃａｌｐｒｏｃｅｓｓｉｎｇ[1,2 ] .Ａｔｐｒｅｓｅｎｔ,ｍｏｓｔｓｃｈｅｍｅｓｒｅｐｏｒｔｅｄｆｏｒｇｅｎｅｒａｔｉｎｇｇｒｅｅｎｂｅａｍｓａｒｅｂａｓｅｄｏｎｔｈｅｆｒｅｑｕｅｎｃｙｃｏｎｖｅｒｓｉｏｎｏｆｎｅａｒ ｉｎｆ…     

Modulated Pulse Generations in a Laser-diode-pumped Passively Q-switched Intracavity-frequency-doubling Nd∶YVO_4 Laser

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｉｔｉｓｅａｓｙｔｏｏｂｔａｉｎｈｉｇｈｈａｒｍｏｎｉｃ ｃｏｎｖｅｒｓｉｏｎｅｆｆｉｃｉｅｎｃｙｂｙ ｐｌａｃｉｎｇｔｈｅｄｏｕｂｌｉｎｇｃｒｙｓｔａｌｉｎｔｏｔｈｅｒｅｓｏｎａｔｏｒｄｕｅｔｏｔｈｅｈｉｇｈｆｕｎｄａｍｅｎｔａｌ ｗａｖｅ ｐｏｗｅｒｄｅｎｓｉｔｙ ,ｗｈｉｃｈｉｓｅｓｐｅｃｉａｌｌｙｓｕｉｔａｂｌｅｆｏｒｔｈｅｈａｒｍｏｎｉｃｃｏｎｖｅｒｓｉｏｎｏｆＣＷｌａｓｅｒｗｉｔｈｍｉｄｄｌｅｏｒｌｏｗｏｕｔｐｕｔｐｏｗｅｒ.Ｉｆｔｈｅ ｐａｓｓｉｖｅｌｙＱ ｓ…     

Stability of a Laser-diode-pumped Cr4+∶YAG Passively Q-switched Nd3+∶YAG Laser

In this paper, the stability of a laser-diode-pumped Cr4+∶YAG passively Nd3+∶YAG Q-switched laser and the influence of the transversal mode structure on the stability are investigated. With the laser operating in TEM00 mode, the pulse energy fluctuation and the repetition rate fluctuation as functions of the repetition rate are measured, and semi-quantitatively and qualitatively analyzed, respectively.     

Diode-pumped doubly passively Q-switched c-cut Nd:GdVO4 1.34 μm laser with V:YAG and Co:LMA saturable absorbers

By simultaneously using both V³⁺:YAG and Co:LMA saturable absorbers in the cavity, a diode-pumped doubly passively Q-switched c-cut Nd:GdVO₄ laser at 1.34 μm is demonstrated for the first time. The average output power, the pulse width and the pulse repetition rate have been measured. The experimental results show that the doubly passively Q-switched laser can generate shorter pulse width with higher peak power in comparison to the singly passively Q-switched laser only with V³⁺:YAG or Co:LMA saturable absorber. At the pump power 13 W, the pulse width has been compressed 83% and the peak power has been improved 15 times, respectively.     

Thermal Lensing, Laser Performance at 1.06 μm and 0.53 μm of a NYAB Laser End-pumped by a Diode-laser-array

The thermal lensing, output characteristics of an end-pumped NYAB laser with high pump power levels and operated at the fundamental wavelength, and the manner of self-frequency-doubling, have been investigated. The thermal lensing in the NYAB crystal was found to be significantly stronger than that in Nd:YVO4 crystal. A maximum output of 3.2 W at 1.06 μm was achieved with an optical conversion efficiency of 29.1％ and an average slope efficiency of 37.5％. These results were found to be slightly inferior to those of Nd:YVO4 crystal. When operated in the fashion of selffrequency-doubling, 23 mW green output was obtained at the incident pump power of 5 W, such inefficient operation was attributed to the large mode size in the NYAB crystal.