A laser-diode-pumped acoustic-optic Q-switched Nd:YVO4 slab laser with a hybrid resonator

Abstract

20591 Laser diode pumped all solid state laser with high repetition has a wide range applications in laser pro cessing, laser radar, medicine and so on due to its com pact structure, long lifetime and high efficiency. To most LD pumped Q switched all solid state lasers, Nd:YVO 4 is a favorite crystal owning to its large emis sion cross section, wide pumping wavelength band width and short upper state life time [1]. Therefore, a great deal of research have concentrated on Nd:YVO 4 by many structures, such as LD pumped grazing inci dence slab laser [2][3][4], LD pumped rod oscillator, amplifier [5][6][7][8][9], self stimulated Raman laser [10], optical parametric oscillator [11] and so on. The three emission lines (1064 [12-15], 914 nm [16,17], and 1342 nm [18,19]) of Nd:YVO 4 were also investigated during the past few years. four stage amplifier, 183.5 W at repetition of 850 kHz was achieved and beam quality was measured to be 1.28 and 1.21 in both directions.LD partially end pumped slab laser with hybrid resonator has been proved to be efficient in high power laser operating with excellent beam quality [20][21][22]. In 2003, with LD pumped electro optically Q switched Nd:YVO 4 structure, 83 W of average power at a pulse repetition rate of 50 kHz with a pulse length of 11.3 ns was achieved and the beam quality M 2 < 1.5 was measured with the same pumping power in con tinuous wave operation [20]. In 2007, using this struc ture as amplifier, Zhe et al.[21] obtained a pulse energy of 3.8 mJ and pulse width of 5 ns Q switched laser at a repetition of 1 kHz with the amplification factor of 11. In this paper, it is the first time that an AO Q switch was used in this structure to obtain high rep etition rate Q switched laser. A 32.1 W, high repetition rate laser diode stack pumped Nd:YVO 4 slab laser was demonstrated under the pumping power of 112 W at the repetition rate of 40 kHz, the pulse duration was measured to be 32.47 ns. At the repetition rate of 20 kHz and pumping power of 90 W, the average out put power and pulse duration were 20.4 W and 20.43 ns, respectively.The experiment arrangement was shown in Fig. 1. The central wavelength of LD stack (including four bars) was 808.6 nm and the emission from each diode laser bar was individually collimated by microlens. After the coupling system, a homogeneous pumping line was generated inside the Nd:YVO 4 slab. The crys tal was 12 × 10 × 1 mm and a cut with the c axis along the 1mm direction. It was dopted 0.3 at % and mounted between two water cooled heats sinks with two large faces (12 × 10 mm). Indium foil was used for Abstract-A 32.1 W laser diode stack pumped acoustic optic Q switched Nd:YVO 4 slab laser with hybrid resonator at 1064 nm was demonstrated with the pumping power of 112 W and repetition rate of 40 kHz, the pulse duration was 32.47 ns. The slope efficiency and optical to optical efficiency were 37 and 28.7%, respec tively. At the repetition rate of 20 kHz and pumping power of 90 W, the average output power and pulse dura tion were 20.4 W and 20.43 ns, ...

Actively Q-switched and modelocked all-fiber lasers

“…Their unique characteristics of high intensities together with relatively low heat deposition ensure precise removal of material during a short interaction time [1]. Among the methods developed to generate these pulses [1][2][3][4][5][6][7][8][9], it was proposed the Q-switching mode-locking technique (QML). It consists in the simultaneous generation of Qswitching [10] and mode-locking (ML) [11] in the same cavity.…”

High peak power picosecond hybrid fiber and solid-state amplifier system

“…Nd:YVO 4 has a large stimulated emission cross section [17,18], a comparatively short upper state lifetime, and wide pumping wavelength bandwidth [19,20]. However, Nd:YVO 4 has low mechanical fracture, thus the pump intensity must be kept under a threshold.…”

Diode-pumped high-repetition-rate acousto-optically Q-switched Nd:YVO4 laser operating at 914 nm

“…Considering the application in remote sensing, pulsed 900 nm lasers will be extremely useful, especially high repetition rate oper ation with a high peak power is in demand for improving the speed and distance in transmission. Usually, the technologies of mode locking or Q switch were used to generate high repetition rate lasers [13][14][15][16]. In the past few years, pulsed quasi three level Nd 3+ doped lasers had been demonstrated by using passively Q switch or acousto-optically (A-O) Q switch.…”