Study On Novel Tm³⁺Doped Solid-state Laser At 2 ?M

2 ?m laser lies on eye,safety wavelength region and has distinctive advantages in many application areas,such as LIDAR,free-space commucation,etc.Meanwhile,2?m laser is also in fingerprint region of many molecules,endowing it important applications in gas detection.In addition,2 ?m lasers can be used as a pump source for mid-far infrared laser and optical parametric oscillator.Therefore,generating 2 ?pm laser radiation has great significance in particle application and scientific research.Compared with fiber laser,crystalline laser has weaker nonlinear optical effect and higher beam quality.Thus,it is superior in generating laser emission with high energy,short pulse duration and high peak power,attracting more and more attention from scholars.In this thesis,Tm3+ doped crystalline laser is studied.Firstly,continuous wave(CW)and wavelength tuning performance of new-type crystals are investigated.Secondly,using acousto-optic modulator,active Q-switching operation of Tm3+ doped crystalline laser is studied.Some novel low-dimension saturable absorbers(SAs)based on transition metal sulphide,topological insulator and nanoparticle are fabricated.Their wideband absorption properties,nonlinear optical absorption at 2 ?m and modulation performance in laser pulse are investigated.SESAM mode-locking performance of some Tm3+ doped crystals is studied.The main content of this thesis is as following:1.The performance of Tm,Y:CaF2 and Tm:YSO crystalline laser in CW and wavelength tuning regimes are investigated.The absorption and emission spectra of Tm,Y:CaF2 crystal is characterized.In CW regime,Tm,Y:CaF2 laser delivers maximum average output power of 453mW.Employing a quartz plate as wavelength tuning component,Tm,Y:CaF2 laser could be continuously tuned within a 190 nm spectrum.The maximum average output power of the Tm:YSO laser in CW regime is 1.26 W and a wavelength tuning range of 126 nm is realized.The Tm:YSO laser could operate on dual-and multi-wavelength simultaneous emission in both CW and wavelength-tuning regimes.2.With the help of acousto-optic modulator,active Q-switching operations of Tm,Y:CaF2 and Tm:Lu2O3 lasers are realized.Repetition rates range from 1kHz to 10kHz.From Tm.Y:CaF2 laser,laser pulses with pulse duration of 280 ns,pulse energy of 335 ?J and peak power of 1.19kW are delivered.For actively Q-switched Tm:Lu2O3 laser,laser pulses with pulse duration of 92 ns,peak power of 6.5 kW are obtained under the modulation frequency of 1kHz.Compared with Tm,Y:CaF:crystal,Tm:Lu2O3 is more suitable for generating laser pulses with short pulse duration and high peak power in Q-switching regime3.Some low-dimensional SAs suitable for 2 ?m are studied,including their saturable absorption properties and their applications in lasers.Using method of ultrasound assisted liquid phase exfoliation,two-dimensional SAs based on MoSe2 and Bi2Te3 nanosheets are fabricated.Their broadband absorption properties and nonlinear optical absorption at 2 ?m are studied.Employing them in LD pumped Tm:LuAG lasers,Q-switched laser pulses with pulse duration of several hundered ns and pulse energy of several tens of ?J are obtained.Using Fe3O4 nanoparticles as raw materials.Fe3O4 nanoparticles SA(FONPs-SA)is facricated,whose broadband absorption properties and nonlinear absorption at 2 ?m are investigated.Employing it in LD pumped Tm:LuAG laser.Q-switched pulsed laser with pulse duration of 600 ns and repetition rate of 94 kHz are obtained.SAs based on silicion nanoparticles are facricated and are then applied in Tm:YAP laser,generating Q-switched laser pulses with pulse duration of 453 ns and reperition rate of 115 kHz4.Continue wave mode-locking performance of Tm:Lu2O3 and Tm:YAP lasers is studied with assistance of SESAM.For the first time,mode-locking operation of Tm:Lu2O3 at 1942nm is realized,delivering mode-locked laser pulses with pulse duration of 3.6 ps and average output power of 119 mW.Using another SESAM with different non-saturable loss,mode-locking operations at 1967 nm is also achieved.generating mode-locked laser pulses with pulse duration of 4.6 ps and average output power of 181 mW.Dual-wavelength mode-locking operation of Tm:YAP laser is realized based on a SESAM.The beating frequency of aucorrelation trace is 0.258 THz and pulse width of beating pulse is 2 ps.