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Passively Q-switched All-Solid-State Blue Laser

Posted on:2009-10-10Degree:MasterType:Thesis
Country:ChinaCandidate:T Z CaiFull Text:PDF
GTID:2178360272989737Subject:Optics
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With the great technology advance of semiconductor,the laser diode(LD) was improved with higher power,higher efficiency and longer lifetime,which results in the fast developing of laser diode pumped solid-state lasers(DPSSL).DPSSL has many advantages,such as all-solid-state, compactness,high efficiency.Moreover the blue laser has many applications.Here the passively Q-switched blue DPSSL is investigated theoretically and experimentally.The main contents of this thesis are:Firstly,we introduce three-level system and four-level system briefly,and then focus on analysis of a Nd:YAG crystal and its quasi-three-level system.Secondly,we review the basic principle of Q-switched and its classification.Then the characteristic of Cr:YAG passively Q-switched is analyzed.Thirdly,the principle of the frequency doubling is introduced briefly.We also analyze and compare several kinds of frequency doubling crystals used in generating blue laser.Then the intracavity frequency doubling characteristic of LBO is analyzed chiefly.Lastly,we study the thermo-lens effect,which affects seriously the performance of the laser output.Based on ABCD's transmission matrix theory,we compare the difference bwtween a linear cavity and a three-mirror-folded cavity.According to our analyses and computations above, choosing Nd:YAG as gain-medium,Cr:YAG as saturable absorber,LBO as frequency doubling crystal,we design a passively Q-switched laser diode-pumped solid-state blue laser,We also measure the average power,the repetition rate,the pulse width and then compute the peak power of 473nm blue laser output when the Cr:YAG located at different positions of the two cavities.Using linear cavity,we get a 473nm pulsed blue laser with a pulse width of 120ns,a peak power of 105w and a repetition rate of 18.6 KHz.Using V-fold cavity and Cr:YAG located in the short arm L2,we get a 473nm pulsed blue laser with a pulse width of 200ns,a peak power of 55w and a repetition rate of 23.9 KHz.If Cr:YAG located in the longer arm L1,we get a 473nm pulsed blue laser with a pulse width of 320ns,a peak power of 37w and a repetition rate of 26.7 KHz.
Keywords/Search Tags:Passively Q-switched, Cr:YAG, 473nm
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