A laser diode end-pumped passively Q-switched YAG/Nd:YAG/Cr4+:YAG burst mode laser at 1064 nm is reported. The maximum burst energy of 13.2 mJ at a repetition rate of 100 Hz is got in a duration of 1 ms. The pulse repetition frequency increases linearly and peaks at 31.1 kHz in the pulse burst, while the pulse width keeps nearly constant around ~2 ns. The highest peak power of 373.7 kW is achieved at 10.2 kHz. The beam quality of passively Qswitched 1064 nm laser is also investigated.
High-peak-power, short-pulse-width cavity dumped Yb:YAG thin disk laser is demonstrated. A constant pulse width of 20.3 ns±0.2 ns is achieved within the frequency region between 10 kHz to 100 kHz. The output peak power achieves 109.8 kW, 37.8 kW and 20.9 kW respectively at 10 kHz, 50 kHz and 100kHz.
An all-diode-pumped Nd:YAG burst-mode laser was demonstrated. A diode-laser-side-pumped Nd:YAG laser with Qswitcher, as laser oscillator, was employed to produce burst pulse directly. When the diode-laser worked at 10Hz and Qswitcher was operated at 10kHz, a maximum burst energy of 456mJ was obtained in the master oscillator with the highest optical efficiency of ~30%. Each burst included 19 pulses in the pumping duration of 2ms. A master oscillator and power amplifier architecture was adapted to scale the burst energy to meet PLIF system applications. The burst energy of 456mJ obtained from laser oscillator was amplified to 2.2J by use of three diode-laser-side-pumped Nd:YAG modules as laser amplifiers. The energy extraction efficiency of each stage was achieved to ~13%, ~22% and ~24%, respectively. The single pulse energy of 1064nm laser at 10 kHz reached to ~116 mJ with pulse width of 9.8 ns and a peak power of ~11.8 MW. The performances of pulse-burst laser we constructed can be better and improved greatly by use of more amplifiers.
Planar laser induced fluorescence (PLIF) diagnosis technology has been widely applied in flow field study and combustion diagnosis. Due to the complexity of the experimental environment of practical PLIF applications, The PLIF diagnostic system needs a good environment adaptation. In this paper, we reported a high energy Nd:YAG MOPA laser with repetition rate of 500Hz, which was applied in PLIF diagnostic system. A diode-laser side-pumped Nd:YAG module, which was pumped from five directions and optimized for better gain distribution, was employed to build a EO Q-switched Nd:YAG oscillator. A stable structure design of oscillator resonant cavity was used to improve the environmental adaptability of Nd:YAG laser. In our environmental adaptation experimentation, the laser oscillator has an energy fluctuation of <5% in the temperature range from 5°C to 45°C. In order to scale the pulse energy to meet the PLIF system requirements, we employed three 2500W diode-laser five-direction-side-pumped Nd:YAG modules as laser amplifiers to build MOPA system. Finally, the laser pulse energy of ~18mJ was amplified to 68mJ at 1064nm. Using KTP crystal as a frequency doubling crystal, we obtained a pulse energy of 35.6mJ at 532nm. The developed Nd:YAG laser has been used in our 500Hz-PLIF diagnostic system successfully.
A high-efficiency, high-repetition-rate burst-mode 1064 nm laser under pulsed 878.6 nm laser diode pumping is demonstrated. Pulses at repetition rates ranging from 10 kHz to 100 kHz are produced during the time period of 1 ms pumping duration by using an acousto-optical Q-switch. The maximum pulse burst energy of 44 mJ at 10 kHz is obtained at the incident pump power of 108.5 mJ, yielding an optical-to-optical efficiency of 40.5%. The shortest pulse width at 10 kHz is 9.4 ns at the maximum pump energy of 108.5 mJ. The peak powers are estimated to be ~468.1 kW and 30.1 kW at 10 kHz and 100 kHz in the burst-mode oscillator.
A stable pulse-burst GdVO4/Nd:GdVO4 laser oscillator with repetition rate up to 500kHz is demonstrated by use of a pulsed diode-laser of Stabilized Wavelength 879nm as the pump source. While the pulsed 879nm LD was operated at the repetition rate of 100Hz and the pump duration was 1ms, the different output characteristics of pulse-burst GdVO<sub>4</sub>/Nd:GdVO<sub>4</sub> laser were obtained by adjusting the repetition rate of A-O Q-switch. When the total pump energy was 120mJ, the pulse number of 100, 200 and 500, the burst energy of 25mJ, 35mJ and 40mJ, the pulse width of 8.5ns, 12ns and 27ns were achieved at repetition rate of 100kHz, 200kHz and 500kHz, respectively. The relative single pulse energies were reached to 250μJ at 100kHz, 175μJ at 200kHz and 80μJ at 500kHz. The peak powers were reached to 29.4kW at 100kHz, 14.6kW at 200kHz and 3.0kW at 500kHz. The M<sup>2</sup> factor was measure to 1.4.
A high-repetition-rate, high-peak-power burst-mode laser for laser-based measurement applications is presented by using a master oscillator power amplifier structure. An laser diode arrays (LDA) side-pumped Nd:YAG acousto-optical (A-O) Q-switched laser serves as the master oscillator. Under pulsed pumping, pulse trains with 2-25 pulses are obtained when the repetition rate changes from 10 kHz to 100 kHz. The maximum pulse burst energy of 31.2 mJ is achieved in the A-O Q-switched pulse burst laser oscillator at 10 kHz. Two LDA side pumped Nd:YAG modules are employed in the amplification stage. After the amplification, the pulse burst energy at 10 kHz reaches ~170 mJ with a single pulse energy of 85.2 mJ and a pulse width of 14.5 ns, generating a peak power of 6.1 MW. At 100 kHz, the total burst energy reaches 220 mJ with a single pulse energy of 8.8 mJ in the pulse burst laser system.