Passive mode-locking of a diode-pumped Nd:CLNGG laser was demonstrated for the first time to our knowledge. The laser operated at a central wavelength of 1061.2 nm with a maximum average output power of 101 mW. The mode-locked pulses have pulse duration of 2.0 ps, a spectral bandwidth of 1.2 nm and a repetition rate of 88.4 MHz. The mode locking of the laser was enabled by a semiconductor saturable absorber mirror (SESAM).

H. Luo;定元 汤;G. Q. Xie;W. D. Tan;怀金 张;H. H. Yu

Optics Communications

2009-1-15

We have experimentally studied the dynamics of an optically pumped NH₃ multitransverse-mode ring laser. We show that, because of the nonlinear interaction of transverse modes, the laser intensity output can be periodic, quasi-periodic, or chaotic. Depending on which transverse modes were involved in the interaction, two kinds of routes to chaos were observed in the laser. When four transverse modes interact, quasi-periodic chaos is found, whereas in the case when just two transverse modes with small frequency separation interact a period-doubling route to chaos at the mode beat frequency is observed. Metric properties of observed chaotic attractors were calculated.

定元 汤;M. Y. Li;N. R. Heckenberg;U. Hübner

Journal of the Optical Society of America B: Optical Physics

1996-9

The passive mode locking performance of a LD-end-pumped Nd:Lu₂SiO₅ laser is experimentally investigated for the first time. The passive mode locking of the laser is initiated with a semiconductor saturable absorption mirror (SESAM). Stable mode-locked pulses with 12.3 ps pulse width, 148.3 MHz repetition rate, and 1.42 W average output power have been demonstrated.

Z. H. Cong;行愚 张;Q. P. Wang;定元 汤;W. D. Tan;J. Zhang;X. D. Xu;D. Z. Li;军 徐

Laser Physics Letters

2011-2

We have experimentally studied the passive Q-switching performance of a Nd: YAG ceramic laser with GaAs saturable absorber. Depending on the laser intensity in the GaAs wafer, the Q-switched laser showed much different performance. The shortest pulse obtained has 4.7 ns pulse width, 6.25 μJ pulse energy and 1.33 kW peak power.

Xie Guoqiang;定元 汤;Kong Jian;Qian Liejia

2007

We report a compact quasi-phase-matched optical parametric oscillator (OPO) using periodically poled MgO-doped LiNbO₃ with different grating periods. The OPO is pumped by a diode-pumped passively Q-switched Nd:YAG laser providing 4.8-ns pulses at 5.4-kHz repetition rate. The OPO generates signal and idler wavelengths tunable in the ranges of 1.5-1.7μm and 2.8-3.6μm, respectively, by changing the crystal temperature between room temperature and 170 °C. The temperature-dependent Sellmeier equation for the extraordinary refractive index of MgO-doped LiNbO₃ is modified in the Mid-IR region, which gives an accurate prediction of the experimental temperature-tuning results. The linewidth of the signal wave is in the range of 0.5-1.0 nm without any controlling element.

H. P. Li;定元 汤;S. P. Ng;J. Kong

Optics and Laser Technology

2006-4

Coexistence of scalar dissipative solitons along the two orthogonally polarized directions of a fiber laser is observed. Due to the large cavity birefringence, the dissipative solitons along different polarization axes have different group velocities.

L. M. Zhao;定元 汤;X. Wu;H. Zhang;H. Y. Tam

2010

This paper presents the theoretical and experimental results of an injection-locked laser (ILL) device constructed by the MEMS technology to provide a wavelength-stabilized laser source for the applications of accurate time keeping. The device mainly consists of a MEMS tunable laser and a FP laser chip by a scheme of external injection. The combination of the injection locking and the MEMS technology produces a stabilized wavelength (< ±0.001 nm) at a small size (3 mm × 2 mm × 0.6 mm); both are crucial for portable atomic clocks.

X. M. Zhang;A. Q. Liu;H. Cai;C. Lu;定元 汤

2005

A passively mode-locked soliton fiber ring laser was successfully demonstrated, and bound soliton pulses with an FWHM pulsewidth of 326 fs and fixed separation of 938 fs were first observed. The number of bound soliton pairs in the cavity can be controlled under lower pump power. The transmission effects were investigated by injecting bound soliton pulses into a single mode fiber.

Yandong Gong;Ping Shum;Tee Hiang; Cheng;Qi Wen;定元 汤

Optics Communications

2001-12-15

Emission pattern of surface-enhanced Raman scattering (SERS) from the junction of single nanoparticle and a metal film was experimentally demonstrated. The presence of a thin metal film enables the excitation of surface plasmon polaritons (SPPs) to greatly improve the excitation efficiency of SERS, which is subsequently coupled back to SPPs and re-radiates into the substrate side with higher refractive index at SPP excitation angle. The so-called surface plasmon coupled emission can serve as a high sensitivity detection tool for SERS and particularly for the tip-enhanced Raman spectroscopy.

Luping Du;定元 汤;Guanghui Yuan;Shibiao Wei;小聪 袁

Applied Physics Letters

2013-2-25

We realized a laser-diode pumped mode-locked Tm:YAG ceramic laser with a semiconductor saturable absorber for the first time to our knowledge, 60 ps laser pulse with 182mW power was obtained at 2007 nm.

Qingfeng Lin;Yuwan Zou;Qing Wang;Zhiyi Wei;Jian Zhang;定元 汤

2013