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Research Of The Characteristics About All-solid-state Picosecond Self-mode-locked Laser At 1.06 Um

Posted on:2017-03-04Degree:MasterType:Thesis
Country:ChinaCandidate:R X YuanFull Text:PDF
GTID:2308330485460450Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
Diode-pumped solid-state laser which can produce ultrashort-pulses with high peak power, short width and high beam quality. The laser in this type is widely used in industrial, military, medical, scientific research and other important because of its high efficiency and stability. All solid-state self-mode-locked picosecond laser is a special form in short-pulse lasers, there is no other extra element in the laser’s resonator. The cavity of the self-mode-locked laser is simple, and the laser can be downsized operation, meanwhile the cost of this kind laser is very low. This paper aims to research LD pumped self-mode-locked picosecond lasers with linear cavity at 1.06 μm. The main contents included in this paper as the following aspects:First, the theoretical research of the self-mode-locked laser has been done, and a number of short linear cavity mode-locked lasers were designed and tested, the main limitations of the mode-locking in the self-mode-locked laser with soft diaphragm were studied. The basis experimental study has been done to determine the short cavity parameters of the self-mode-locked laser.Second, an effective Nd:YVO4 self-mode-locked picosecond laser has been designed, the transmittance of the output mirror at 1.06 um is T = 10%. The resonator cavity is plane-concave cavity, and the radius of the pump spot is 150 um, a concentration of a-cut 0.2% Nd-doped YVO4 crystal was selected as the laser gain medium, both of the ends are coated film of high transmittance at 1.06 um, the medium size is 3 x 3 x 10 mm. When the incident pump power is 6 W, the output of the laser is 2.6 W. Meanwhile the laser output stable continuous mode-locked pulses, the repeat frequency of the pulses is 1.34 GHz, the width of the pulse is in the order of ps, the center wavelength is 1064 nm, since the slope efficiency of this mode-locked laser is 52.1%.Third, the research of the output characteristics in Nd:YVO4 self-mode-locked picosecond laser has been done. Select an a-cut 0.2% doped Nd:YVO4 crystal, wedged 1°at both ends to suppress the Fabry-Perot etalon effect, and the size of the crystal is 3×3×10 mm. The quasi-periodic self-mode-locked pulses, the period-doubling self-mode-locked pulses and the chaotic state of the picosecond laser were observed and analyzed. Meanwhile, comparative study of the output characteristics about four output endoscopic laser at 1064 nm with the transmittance are 10%,20%,30% and 50% has been done to optimize the design of the laser.Fourth, experimental study of Nd:YAG self-mode-locked laser at high repetition rate has been conducted. Resonator to operate in experiments is at the edge of the stable area, which is a flat-concave cavity, the radius of curvature of the input mirror is 50 mm, the cavity length is 46 mm, the transmittance at 1.06 um wavelength of the output mirror is 10%. There are high power density in the cavity when normal pumping. When the incident pump power exceeds 3 W, operation of self-mode-locked laser began, the repetition rate of the pulses is 2.55 GHz, center wavelength of output pulsed laser beam is 1064 nm. When the pump power is 15 W, the laser output power to maintain the clamping operation up to 6.71 W by optimizing the laser cavity length, the slope efficiency of the laser is 45%.
Keywords/Search Tags:self-mode-locking, Nd:YVO4, Nd:YAG, Kerr effect, output characteristics
PDF Full Text Request
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