Research On LD End-pumped 532 Nm Nd:YVO₄/MoS₂ All-solid-state Passively Mode-locked Laser

All-solid-state laser is a laser generator with laser diode（LD）as pump source and solid laser material as laser gain medium.With the advantages of small size,light weight,high efficiency,long life,stable performance,good reliability,good beam quality,it is widely used in scientific research,information transmission,industrial processing,biomedical,military defense and other fields.Among them,the all-solid-state passively mode-locked laser with the characteristics of narrow pulse width,high repetition rate and high peak power is the research hotspot in recent years,which has attracted great attention.In this paper,a five-mirrors W-type laser resonator was designed with the nonlinear two-dimensional material molybdenum disulfide（MoS₂）as the saturable absorber（SA）.The 1064 nm and 532 nm all-solid-state passively mode-locked lasers were realized respectively,and the mode-locked laser output with picosecond（ps）pulse width was obtained.The contents are concluded as follows:1、The research status of all-solid-state laser at home and abroad,three common nonlinear two-dimensional materials,characteristics and applications of mode-locked laser are introduced in detail,and the development trend of passively mode-locked technology is summarized.The basic theory of mode-locked laser is analyzed.The principle of nonlinear saturable absorption of MoS₂ and its related characteristic parameters are studied.The mode-locked technology based on saturable absorption is introduced.2、The preparation and characterization of MoS₂ SA were studied.MoS₂ SA was prepared by lithium ion intercalation method,and its microstructure and morphology were analyzed by a series of characterization methods.The design and construction of the laser resonator were introduced emphatically,and the five mirrors W-type laser resonator was designed.3、The LD end-pumped Nd:YVO₄/MoS₂ all-solid-state passively mode-locked laser was constructed.The 1064 nm mode-locked laser with a maximum output power of 894 mW,a pulse width of 5 ps,a repetition rate of 87.2 MHz and an optical-optical conversion efficiency of 13%was obtained.The 532 nm mode-locked laser with a maximum output power of 757 mW,a pulse width of 3.5 ps,a repetition rate of 87.2MHz and an optical to optical conversion efficiency of 8.8%was obtained by optimizing the parameters of the laser cavity and placing the second harmonic crystal PPLN in the proper position in the cavity.