## 1 Introduction  
Compact diode-pumped solid state lasers with high-energy sub-nanosecond pulses at kHz repetition rates have a variety of applications, such as laser ranging [1, 2], materials processing [3], nonlinear optical conversion [4, 5] and Mid-IR optical parametric processes [6, 7, 8, 9, 10], etc. The scaling of energy from sub-nanosecond oscillators is strongly limited by optical damage and thermal effect. Laser radiation with high beam quality, short pulse duration, high repetition rate, and high intensity can be obtained with the Master Oscillator Power Amplifier (MOPA) approach [11, 12]. Both Yb\({}^{3+}\)-doped lasers [13] and Nd\({}^{3+}\)-doped lasers [14] can use the MOPA approach to achieve high energy sub-nanosecond pulses near 1 \(\upmu\)m. Yb\({}^{3+}\)-doped lasers have wide gain bandwidth, high Stokes efficiency, and high saturation fluence and achieve pulse energy with hundreds of mJ. In Yb\({}^{3+}\)-doped lasers, cryogenic cooling is needed to acquire a four-level system, which will increase complexity of laser system [15, 16]. Nd\({}^{3+}\)-doped lasers with four-level systems operating in room temperature have higher gain and simpler structure, making them more attractive. Several diode-pumped solid-state sub-nanosecond laser systems with different Nd\({}^{3+}\)-doped materials geometry have been reported recently. A Nd\({}^{3+}\)-doped amplifier in bounce geometry has higher small-signal gain to amplify sub-nanosecond oscillator with low energy and high repetition. A sub-nanosecond laser using a side-pumped Nd:YVO\({}_{4}\) bounce amplifier operating at 1-10 kHz was demonstrated with 577 ps duration and 545 \(\upmu\)J energy (1 MW peak power) in 2010 [17]. In a 2011 study, a sub-nanosecond Nd:YAG laser system with bounce geometry has been reported, the output energy of which was 0.8 mJ with peak power of 9.35 MW [18]. However, due to the small volume of the active medium, the pulse energy of a sub-nanosecond laser using bounce geometry is less than 1 mJ. In comparison, Nd\({}^{3+}\)-doped lasers based on bulk crystal may acquire high pulse energy at the kHz level [19; 20; 21]. A sub-nanosecond single frequency MOPA laser system operating at 500 Hz was reported, which generated pulses with a width of 830 ps, energy of 13 mJ, peak power of 15.7 MW, and M\({}^{2}\) < 1.4 [22]. A Nd:YAG laser system based on the MOPA approach operating at 300 Hz and using selectable 350-600 ps nominally flat temporal pulse shape has been reported, which generate pulses with 127 mJ energy and maximum peak power of 400 MW [23], but beam quality M\({}^{2}\) were not measured. As is already known, beam quality always gets worse due to thermally induced birefringence in Nd:YAG crystal [21; 24]. Laser systems based on end-pumped bulk Nd:YVO\({}_{4}\) crystal have better beam quality because of natural birefringence architecture, which can alleviate thermally induced birefringence [25; 26; 27]. At the same time, Nd:YVO\({}_{4}\) is a self-excited Raman scattering crystal [28; 29; 30]. Stimulated Raman scattering (SRS) is a third-order nonlinear optical effect, which must be taken into consideration in high peak power amplification. Through the SRS process in YVO\({}_{4}\) crystal, 1064 nm fundamental wave will be converted to Raman light, which consists of different Stokes waves, such as first Stokes wave \(\lambda\) = 1176 nm. Raman light brings in many disadvantages, for example, Raman light consumes amplified fundamental pulse energy and reduces the amplification efficiency. Morever, Raman light with high peak power may enter into the end-pumped laser diode and leads to damage of the laser diode. Because of this, the SRS process should be averted to improve amplification efficiency and keep optical components safety. In this paper, we present a Sub-Nanosecond Nd:YVO\({}_{4}\) MOPA system consisting of a master and a series of amplifiers. By suppressing the SRS process during amplification, we obtain 65.4 mJ energy at 1064 nm with 600 ps and peak power above 100 MW at 1 kHz.