Characteristics Of Diode-pumped Tm³⁺ Co-dopedpulse Lasers

The 2?m band laser is a good light source for surgery because of its shallow penetration depth to human tissues,safety to human eyes and optical fiber transmission.In addition,because of its good transmission to the atmosphere,it has become an ideal light source for laser rangefinder,coherent doppler radar,differential absorption radar and so on.It has a broad application prospect in remote sensing and optical communication.At the same time,it is also an ideal pump source for the optical parametric oscillator at the wavelength of 3⁵?m and 8¹2?m.The study of 2?m band lasers with high efficiency,miniaturization,long lifetime and stable performance is one of the main research directions of the next generation solid-state lasers."One generation material,one generation device",laser diode pumped Tm³⁺doped rare earth ions to produce lasing,which is still the most effective technology way to get2?m band laser directly.In this paper,the characteristics of three kinds of Tm³⁺co-doped calcium fluoride crystals are characterized by continuous laser and pulsed laser.The content of this paper is divided into the following aspects:1.This paper introduces the background and the research significance of 2?m band laser.This paper systematically describes the history of ytterbium-doped lasers and analyzes the crystal structure and advantages of co-doped calcium fluoride.At the same time,the theory of2?m band solid-state laser is briefly introduced.2.We analyzed the properties of diode-pumped continuous wave and passively Q-switched Tm,Y:CaF₂ lasers.The spectral properties of Y³⁺doped Tm:CaF₂ crystal are introduced firstly and the continuous laser experiments are carried out.The maximum output power of the output mirror with a transmittance of 2%is 1.103W and the corresponding oblique efficiency is 51.53%.Secondly,the tunable laser wavelength of Tm,Y:CaF₂ crystal is161 nm.Finally,the passively Q-switched pulse laser was obtained by using graphene oxide as a saturable absorber.The experimental results show that the narrowest pulse width is 1.316?s,the maximum pulse repetition is 20.22 kHz,the corresponding single energy and maximum peak power are 20.4?J and 15.5 W.3.The CW laser and the passively Q-switched laser output of diode-pumped Tm,Gd:CaF₂ crystal have been realized.In this chapter,we study the spectral properties and the continuous wave output characteristics of Tm,Gd:CaF₂ crystal.When the pump power is2.859W,the absorption coefficient of the crystal is 39.82%.The obtained CW maximum output power is 1.067W and the oblique efficiency is 43.42%.Tunable experiment using birefringent filter obtain continuous laser in the range of 175 nm.The preparation process of a new two-dimensional material,Mxene Ti₃C₂,is introduced.It is used as a saturable absorber to realize pulsed laser operation.When the absorption pump power is 2.85 W,the minimum pulse width is 2.39?s,the maximum repetition rate is 19.61 kHz and the maximum single energy is 10.603?J.4.The CW laser,continuous tuning laser and passively Q-switched laser output of diode-pumped Tm,Gd:CaF₂ crystal have been realized.A high CW output power of more than4W is obtained,with an oblique efficiency of 67.8%,and a tunable range of 192 nm has been successfully realized at the same time.The passively Q-switched pulse lasers were obtained by using Cu₁₂Sb₄S₁₃3 nanocrystalline materials.When the absorption pump power is 3.97 W,the minimum pulse width is 1.24?s,the maximum repetition rate is 26.58 kHz and the maximum single energy is 15.29?J.The passively Q-switched mode-locked laser is obtained by using SESAM.The results showed that the crystal of Tm,La:CaF₂ had great development potential in obtaining ultra-fast laser operation at 2?m band.