An experimental time trace which shows before modulation the laser output is chaotic. When the modulation is applied, there is at first a non-periodic transient. Then the trajectory is phase space settles on a limit cycle created by the pump modulation, and results in period-4 pulsations in the laser output. When the modulation is removed, chaotic dynamics reasserts itself.
G. Kociuba;定元 汤;N. R. Heckenberg
1999
Passive mode locking of Nd:Lu2.9Gd0.1Al 5O12 (Nd:LuGdAG) crystal lasers was experimentally investigated. Stable mode-locked pulses with pulse widths as short as 9.7 ps were obtained for the Nd:LuGdAG crystal; the corresponding maximum output powers were 0.93 W while the mode-locked slope efficiencies were 43%, among the highest efficiencies ever reported for Nd3+ ps lasers. The results demonstrate that Nd:LuGdAG garnet crystal is a promising gain medium for efficient picosecond laser use.
J. Q. Di;X. D. Xu;长泰 夏;W. D. Tan;J. Zhang;定元 汤;D. Z. Li;D. H. Zhou;F. Wu;军 徐
Laser Physics
2013-5
We have demonstrated an efficient diode-end-pumped continuous-wave Tm:YAG ceramic laser at 1962 nm using a compact two-mirror cavity. The laser oscillation at 1962 nm was realized by increasing the cavity loss at 2016 nm to limit oscillation with the strongest laser gain. For comparison, two different output couplers were used to build single wavelength lasers operating at 1962 and 2016 nm. A laser output power of 2.06 W at 1962 nm was achieved for an absorbed pump power of 6.59 W with the laser ceramic temperature maintained at 15 °C. The corresponding slope efficiency and conversion efficiency were calculated to be 37.8% and 31.3%, respectively. In contrast, the maximum output power at 2016 nm was approximately 3.47 W under the same conditions. The 1962 nm laser has potential application in the analysis of CO2 and HBr molecular gases.
Haiyong Zhu;Yongchang Zhang;Jing Zhang;Yaoju Zhang;Yanmin Duan;Xiukai Ruan;Jian Zhang;定元 汤
IEEE Photonics Journal
2017-12
We have experimentally studied the passive Q-switching performance of a Nd:YAG ceramic laser with GaAs saturable absorbers. It was found that, depending on the laser intensity in the wafer, the Q-switched pulses obtained could have very different pulse width and pulse energy. The shortest pulse obtained has 4.7ns pulse width, 6.25νJ pulse energy and 1.33kW peak power. Furthermore we show that, by adding a slit in the cavity, the Q-switched pulse stability could be significantly improved.
Guoqiang Xie;定元 汤;Jian Kong;列加 钱
Journal of Optics A: Pure and Applied Optics
2007-7-1
We report fabrication of a normal dispersion thulium-doped fiber with a W-type index profile. The fiber is employed in a ring cavity to demonstrate mode-locked laser near 2 μm with a saturable absorber.
Yuhao Chen;Siddharthan Raghuraman;Daryl Ho;定元 汤;Seongwoo Yoo
2018
Transparent 0.6 at% Nd:Y2O3 ceramics were fabricated by vacuum sintering at 1550°C and hot isostatic pressing (HIP) at 1540°C. The ceramics sintered at such temperatures had good homogeneity with dense microstructures, without any residual pores and secondary phases. The in-line transmittance reached 81.6% at 1000 nm and remained 81.1% at 650 nm. Continuous wave (CW) laser operation of an uncoated ceramic slab was evaluated. A maximum output power of 3.6 W with slope efficiency of 45.2% at 1.08 μm was obtained.
Danlei Yin;Jun Wang;Peng Liu;Haiyong Zhu;Bingqing Yao;Zhili Dong;定元 汤
Journal of the American Ceramic Society
2019-12-1
We report on a diode -pumped passively mode -locked Yb :Y2O 3 ceramic laser by using a GaAs wafer simultaneously as saturable absorber and output coupler. Mode-locked pulses of 1.1 ps with repetition rate of 125 MHz are achieved.
J. Kong;定元 汤;J. Lu;K. Ueda
OSA Trends in Optics and Photonics Series
2004
We demonstrate a 2097nm Q-switched Ho:YAG ceramic laser resonantly pumped by a Tm:YLF laser. The Q-switched pulse energy was 9.6 mJ at a pulse repetition frequency (PRF) of 200 Hz and 10.2 mJ at a PRF of 100 Hz, respectively. The M2 factors were measured to be less than 1.1 in both directions.
Lei Wang;春清 高;Mingwei Gao;Yan Li;Fuyong Yue;Jian Zhang;定元 汤
2013
A silicon microelectromechanical system (MEMS) variable optical attenuator with fibre connection is reported. The device requires only 8 V driving voltage. It has only 1.5 dB insertion loss, but 45 dB dynamic range, 37 ms response time, and 0.9 dB wavelength dependence loss over the C-band (1528-1561 nm).
X. M. Zhang;A. Q. Liu;C. Lu;定元 汤
Electronics Letters
2002-4-11
Yb:LuAG laser ceramics with different Yb3+ doping concentrations were successfully fabricated by using a solid-state reactive sintering method. SEM graphs demonstrate that the samples have a dense and pore-free microstructure. Based on the spectroscopic studies the ceramics have a large emission cross-section of 2.7 × 10-20 cm2 at 1030 nm emission peak. CW laser operation of the samples has given 7.2 W output power with 65% slope efficiency.
Dewei Luo;Jian Zhang;Changwen Xu;Hao Yang;Hui Lin;Haiyong Zhu;定元 汤
Optical Materials Express
2012-10