The Research On Generation,Amplification,Wavelength Conversion And Equipment Prototype Of LD-pumped All-solid-state High Repetition Rate Nd:YVO₄ Picosecond Laser

Ultrafast lasers with pulse duration from a few picoseconds to tens of picoseconds are widely used in science,medical and industrial applications.The LD-pumped all-solid-state picosecond lasers have the advantages of small volume,low cost and long life,and the Nd:YVO₄ crystal also has the advantages of low cost,excellent physical properties and large emission cross section.Using SESAM passive mode-locking,the picosecond oscillator based on the Nd:YVO₄ crystal can achieve a mode-locked pulse sequence with a repetition rate from MHz to GHz.After amplification and wavelength conversion,a picosecond laser with high average power,large pulse energy and different wavelength can be obtained.In this paper,a research on generation,amplification,wavelength conversion of LD-pumped all-solid-state Nd:YVO₄ picosecond lasers is achieved.Based on these researches,the research of equipment prototype is did,and some prototypes of ultrafast laser are designed and built.The high repetition rate Nd:YVO₄ picosecond mode-locked laser has been widely used in biological image,high-speed optical communication and high-repetition-rate optical frequency comb.And some research on the high repetition rate Nd:YVO₄ picosecond mode-locked laser is did for this purpose,the laser is consisted of a high repetition rate oscillator and a single pass amplifier.Finally,a laser with 3.24 GHz of repetition rate,11.3 W of average power and 11.4 ps of pulse duration was achieved.To the best of our knowledge,it is currently the highest average power in GHz picosecond mode-locked laser,and related work has been published on Chinese Physics B,2019,28?5?:054205.The high repetition rate Nd:YVO₄ picosecond laser based on repetition rate multiplier can generate picosecond green laser with high repetition rate by SHG,and this kind of high repetition rate green laser can be used of pumping high repetition rate OPO.So some research on the high repetition rate Nd:YVO₄ picosecond laser based on repetition rate multiplier and the SHG is did for this purpose.The laser is consisted of a seed source,a four stages repetition rate multiplier,a two stages single pass amplifier and a SHG.The seed source is a commercial picosecond mode-locked laser with 2 W average power,68 MHz repetition rate and 8.3 ps pulse duration.Finally,a laser with 1.08 GHz of repetition rate and8.7 ps of pulse duration was achieved,and a SHG with 2.51 W average power is achieved by a KTP crystal,the corresponding SHG efficiency reached 24.7%.To the best of our knowledge,it is the first high repetition rate picosecond SHG.The amplified high repetition rate Nd:YVO₄ picosecond laser is an ideal light source in scientific research and industrial production,and it can be used in OPA,synchronous pumping and laser micromachining,especially in the field of hard material cutting,it has a unique advantage.And some research on high repetition rate Nd:YVO₄ picosecond laser amplifier and wavelength conversion is did for this purpose.The amplifier is composed of a seed source,a high repetition rate regenerative amplifier,a two stages single pass amplifier and a wavelength converter.Finally,a amplified laser with 24 W of average power,500 kHz of repetition rate and 13.4 ps of pulse duration was achieved,and a high efficiency frequency conversion with SHG power of 12.7 W and THG power of 9.25 W is realized by LBO crystal at the input average power of 23.2 W for baseband laser,the corresponding optical-optical conversion efficiency reached 54.7%and 39.6%,respectively.Corresponding results have been published in Acta Physica Sinica 2019,68?12?:124205.When picosecond laser used in scientific research and industrial production,a stable and reliable laser product is needed to be designed.Some instrumental researches including the visual laser housing design method and the paste mirror holders are did for this purpose,and the results of these instrumental researches have been used to design and build some prototypes include of the compact high power picosecond Nd:YVO₄ oscillator prototype with paste mirror holder.All these prototypes have been used in many clients and get a well feedback.