Preparation And Characterization Of MoS₂ And Its Application In Solid State Lasers

Ultrashort pulse laser has many advantages,such as narrow pulse width in time domain and wide spectrum in frequency domain.It has important applications in many fields such as optics and electricity.How to successfully obtain high power,high repetition frequency and high pulse energy lasers has been a research hotspot in the field of ultra-short pulse lasers.In recent years,graphene-like two-dimensional materials represented by molybdenum disulfide?MoS₂?have been widely used in ultra-fast pulsed lasers because of their adjustable bandgap,high modulation depth,wide-band saturable absorption and superior properties to traditional semiconductor optical saturable absorbers?SAs?.In this paper,the preparation and characterization of MoS₂ SA are mainly studied,and SA is applied in all-solid-state pulsed laser system by its excellent optical properties.The specific contents are as follows:?1?MoS₂ solution was prepared by lithium ion intercalation method,and MoS₂ SA with excellent performance was successfully obtained.MoS₂ SA was characterized by Raman and AFM.The results show that the SA surface film exhibits a large-scale layered two-dimensional nanostructure with a thickness of about 2-7 layers.Subsequently,the transmittances of MoS₂SA at 1064 and 532 nm are 87.6%,87.09%,modulation depth is 4.3%,saturated light intensity is 7.5 MW/cm²,respectively,showing good optical properties.Compared with common CVD methods,this method has the advantages of simple process,high peeling efficiency and wide range.MoS₂ prepared by this method has better dispersibility in water and is easy to obtain SA with excellent performance.?2?Emphasis is placed on the research and construction of a 1064 nm all-solid-state pulse laser system,and the stable output of 1063.9 nm picosecond mode-locked laser based on MoS₂SA is achieved.When the absorption pump power of the laser is 3.43 W,the laser system starts to operate continuously mode-locked?CWML?;when the power is 6.86 W,the average output power is 894 mW,which corresponds to the optical-optical conversion efficiency of 13.03%and the slope efficiency of 16.45%.Meanwhile,mode-locked pulse FWHM is 1.89 nm,pulse width is 5 ps,repetition frequency is 87 MHz,signal-to-noise ratio of spectrum signal is 45.1dB.Compared with similar experiments in the existing literature,the output pulse width in this paper is narrower,the signal-to-noise ratio of the spectrum signal is higher,and the laser system is more stable.?3?By theoretical research and numerical simulation,a 532 nm all-solid-state CW and pulsed laser system is reasonably designed in combination with the actual experimental environment,and the corresponding laser performance is discussed.The 532 nm all-solid-state pulse laser system is studied emphatically,and the 532.7-nm nanosecond Q-switched laser output based on MoS₂ SA is realized.When the pump power of the laser is 6.21 W,the maximum average output power is 323 mW,the corresponding optical-optical conversion efficiency is 5.3%and the slope efficiency is 6.9%.The pulse repetition frequency is 66.7 kHz and the pulse duration is 320 ns.Compared with similar experiments in the existing literature,the output pulse width is further compressed at ns level by optimizing the laser system design.