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Research On All-solid-state Pulsed Lasers Based On Novel Saturable Absorbers And Self-made SESAM

Posted on:2018-06-18Degree:MasterType:Thesis
Country:ChinaCandidate:J YaoFull Text:PDF
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LD(Laser Diode)side pumped all solid-state pulse laser has a compact structure,well stability,pulse width,high frequency,wide spectrum,low cost,and many other advantages.LD side pumped all solid-state pulse laser in the military,engineering,medical and scientific research in the areas of application is of great significance.Currently SESAM(Semiconductor saturable absorber mirrors)as saturable absorber is used in solid-state laser pulse material choice,SESAM techology and solid mode-locked lasers with SESAM have become mature in abroad,but in the initial stage in China.Due to the side of the pump's own characteristics,Currently in domestic end pump mode-locked laser with SESAM research is significantly more than side of the pump lasers;But SESAM have a complex preparation process,high cost and difficult to adjust the parameters.In recent years such as Carbon nanomaterials?semiconducting transition metal dichalcogenides and so on new broadband saturable absorber applied to the pulse laser have receive more and more attention.Based on the above background,this thesis around new broadband saturable absorber with homebred SESAM applied to LD side pumped solid-state laser is studied.The main contents of thesis and innovations are as follows:1.Solved the choice of laser crystal and of the ways of LD pumped,theoretically analyzes the LD side pumped solid state laser thermal effect phenomenon.Advanced the theory of crystal thermal lens measurement method,and used asymmetric resonator measured the thermal lens length of the crystal versus the pump current.2.In this paper,the ABCD matrix theory of Gaussian beam propagation in resonant cavity is introduced,and the application of ABCD in resonant cavity design is described with flattened linear cavity as an example.The design method of three-mirror folding cavity is introduced,and the application of equivalent mirror method in the design of four-mirror folding cavity is introduced.3.The broadband saturable absorption solution were preparated by the liquid phase exfoliation method,used the vertical growth method preparated transmitted carbon nanotubes saturable absorbers,used drip-smear method preparated WS2 saturable absorber mirror.Used spectrophotometer characterize the transmittance and absorption rate of saturable absorber material used in the experiment.4.The single-walled carbon nanotubes broadband saturable absorbers were used to experiment with LD side-pumped straight-line and folded-cavity Q-switched lasers.The wavelength was 1064nm and the shortest pulse width was 1.12?s.the repetition frequency was from 21.11KHz to 44.6kHz,the maximum output power was 50 mW,the single pulse energy was 1.12?J,the peak power was 1W;the shortest pulse width was 1.25?s in the folding cavity,Single pulse energy of 3.60?J,peak power of 24.48W,the repetition frequency was from 22.05kHz to 25.49kHz,the maximum output power was 780mW.5.Experimental study of LD side pumped folding cavity WS2 Q-switched lasers,the laser wavelength is 1064nm,the shortest pulse width is 3.205?s,the repetition frequency is from 38.91kHz to 71.70kHz,and the maximum output power is 466mW.6.The LD side-pumped SESAM mode-locked laser was designed to have a small spot area at SESAM.The laser wavelength was 1.06?m,the pulse width was 267.05ps,the maximum output power was 456mW,beam mass M2 factor was 1.07.7.Design and build a titanium sapphire W-type cavity Q-switched mode-locked lasers,the laser wavelength was 824nm,the maximum output power was 1.78W,and the conversion efficiency of the laser was 18.9%.Innovations:1.Use WS2 nanometer film and PVA combination,dropping in the 1064 high mirror,and ultimately made WS2 saturable absorption mirror.This form of absorber surface is more smooth,doped WS2 nanoplate is more uniform,is conducive to achieving a stable pulse output.2.Using four-mirror Z-type folding cavity structure,to achieve a high output power of the passive Q-switched operation.Q-pulse energy up to 6.5p?J,in the relevant research reports are better results.
Keywords/Search Tags:LD side-pumping, diode pump solid state laser, broadband saturable absorber, semiconductor saturable absorber mirror, passive Q-Switched, passive Mode-locking
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