The Study On Diode Pumped High-power Mode-locked Laser

Diode pumped solid state lasers(DPSSL) have the advantanages of high efficiency, high stability, compact structure and good beam quality. DPSSLs have been widely applied in science research, industrial processing, medical applications and military detection. Nowadays,the study on DPSSL, especially on LD pumped mode-locked solid state laser, have been a very important part for the laser development. Efforts should be made to investigate and improve laser performances of different laser crystals.In our work, we chose LD as pump source and studied the laser performance of two kinds of laser crystal, Yb:LuAG and Nd:YVO4. The whole thesis included following chapters:① The background and development of solid-state laser, includingchapter 1② The principle of mode-locking and the introduction ofSESAM(semiconductor saturable absorber mirror), includingchapter 2③ Study on wavelength-switchable Yb:LuAG mode-locked laser,including chapter 3④ Study on LD pumped high-power Nd:YVO4 mode-locked laser,including chapter 4⑤ The summary and future work, chapter 5In chapter 1, we begin with the first solid-state laser in 1960, and introduce the development of DPSSL. We mainly discuss the development of pump source and mode-locking technology.In chapter 2, we introduce the principle of mode-locking and the structure of semiconductor saturable absorber mirror(SESAM).In chapter 3, we report a wavelength-switchable mode-locked Yb:LuAG laser. In the experiment, we used 10 at.% doped Yb:LuAG crystal with 3 mm length, and realized stable output with wavelength-switchable mode-locked pulses. Our laser could generate 1.15 ps pulses with center wavelength at 1031 nm or 252 fs pulses with center wavelength at 1046 nm. The maximum average output power reached 2.2 W. Different pulses with picosecond or femtosecond pulse duration could be very useful when pumping the optical parameter oscillator(OPO).In chapter 4, based on thermal bonded Nd:YVO4 crystal, we obtained picosecond mode-locked pulses with maximum average output power of 47.5W, which was the highest output power ever reported domestically. In this work, we used pump source with center wavelength at 888 nm and thermal bonded Nd:YVO4 crystal to reduce the heat load in laser crystal. Theoretically, we analized the temperature distribution of Nd:YVO4 crystal with FEA method. Experimentally, we pumped(5+30+5) mm thermal bonded YVO4-Nd:YVO4-YVO4 crystal with 100 W pump at 888 nm, generating mode-locked pulses with 47.5 W average power.In chapter 5, we have a summary of our work. We reported a wavelength-swithable mode-locked Yb:Lu AG laser. The Yb:LuAG laser could be very useful in pumping optical parameter oscillator to generate mid-infrared pulses. Our mode-locked Nd:YVO4 resonator reached the highest average power domestically. Its high-power picosecond pulses could be applied to wafer process.