Exploiting Nd:YVO4/Nd:GdVO4 dual gain media to generate SESAM-based dual-mode-locked laser

• Main Authors: Chang, Feng-Lan, 張鳳蘭
• Other Authors: Chen, Yung-Fu
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/5sgpb9

博士 === 國立交通大學 === 電子物理系所 === 106 === We develop the passively mode-locked (PML) operation in diffusion-bonded gain media by parallel-bonded and wedged-bonded structures. Both approaches are utilized in a simple linear cavity. Firstly, we experimentally found that , with SESAM-based, the parallel-bonded Nd:YVO4 and Nd:GdVO4 lasers can operate at the stable CW mode-locked state with the repetition rates of 300 MHz. The temporal trace shows multi-pulse mode-locked pulse trains with the cavity round-trip time of 3.36 ns, and it exhibits 7 mode-locked pulses in the single group with delay time of 160 ps. At an incident pump power of 12.7 W, the maximum output power of 2.6 W is obtained. The main peak width in the mode-locked pulses can be evaluated as 16.3 ps with assuming the Gaussian-shaped profile. The full modulation in every peak indicates the dual-central-wavelength mode-locked pulses to be well synchronous. In order to avoid the multi-pulse temporal structures, we use the wedged-bonded crystal to replace the parallel-bonded crystal. Then, we theoretically and experimentally confirm that we can flexibly control the power ratio of dual-center-wavelengths of 1064- and 1063-nm radiations with wedged-bonded Nd:YVO4 and Nd:GdVO4 gain media. Under the balanced dual-wavelength intensities, the maximum total output power of 2.5 W can be obtained at a pump power of 11 W. In the synchronous dual-wavelength mode-locked operation, the pulse repetition rate and the pulse duration are found to be 297.9 MHz and 24.7 ps. Moreover, the perfect temporal overlapping between the two-wavelength pulses incur a full modulation of optical beating with 1.8 ps pulse duration and 0.318 THz repetition rate. Finally, we have employed a linear three-mirror cavity to achieve the simultaneous harmonically self-mode-locking (SML) laser by the wedged-bonded Nd:YVO4/Nd:GdVO4 at 1063 and 1064 nm. In the long linear cavity setup, we utilized the method of couple-cavity to achieve the sixteenth harmonically self-mode-locking.