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Study On High Power Diode Pumped Solid-state Laser With The Double-pass Amplifer

Posted on:2007-03-16Degree:MasterType:Thesis
Country:ChinaCandidate:Q S GaoFull Text:PDF
GTID:2178360218462405Subject:Optics
Abstract/Summary:PDF Full Text Request
In recent years, diode-pumped solid-state lasers have significantly enhanced the performances of solid-state lasers giving a higher efficiency and a higher average output power at both fundamental and frequency-doubled wavelengths. High-efficiency high-brightness operation of diode-pumped solid-state lasers is attractive for the applications of material processing and remote sensing and as a pump source for frequency conversion. A diode pumped E-0 Q-switched MOPA solid-state laser with output pulse energy of 0.4J at 400Hz repetition rate and 18ns pulse width is demonstrated. The beam quality is less than 2.1.For the output energy and the energy extract efficiency of the doble-pass amplifer were studies by theoretial analysis,numerical simulation and experiment research,which will provide references for the experimental study and design of laser amplifer. The energy extract efficiency of two Nd:YAG rods pumped by diode laser module is experimentally investigated. The output energy and extract efficiency of the each amplification in different input energy are analyzed by theory and experiment.Thermal effects such as the thermally induced lens and stress-induced birefringence of the laser rod pumped by high power LD in laser amplifier and their compensations are discussed. Minus lenses can make good compensation for the thermally induced lens of the laser rod. The depolarization loss caused by the birefringence is reduced with a 90°quartz rotator and imaging relay optical system between two similar laser modules. The output power and the efficiency of laser are both improved in experiment. Phase conjugation technology with liquid CH3COCH3 as medium to improve beam quality in double-pass amplifier laser system is experimentally investigated. The results operating on 400Hz repetition rate show that the thermal effect of the liquid medium can be effectively reduced when the beam scanning system is adopted. The maximum SBS reflectivity of 65%by using of CH3COCH3 liquid is achieved at 400Hz. In additional, the pulse width of laser has been compressed to 5ns, and the beam quality has been improved from 2.3 to 1.3. The quartz glass phase conjugator in a high power and high repetition rate diode pumped Nd:YAG MOPA system is developed. A stable phase conjugating reflection is realized at 400Hz repetition rate and with the reflectivity 40%. The output beam M2 is improved from 2.3 to 1.2.
Keywords/Search Tags:diode laser, laser amplifer, thermal effects, Phase conjugation technology
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