We experimentally demonstrated that few-layer black phosphorus (BP) could be used as an optical modulator for solid-state lasers to generate short laser pulses. The BP flakes were fabricated by the liquid phase exfoliation method and drop-casted on a high-reflection mirror to form a BP-based saturable absorber mirror (BP-SAM). Stable Q-switched pulses with a pulse width of 620 ns at the wavelength of 1046 nm were obtained in a Yb:CaYAlO4 (Yb:CYA) laser with the BP-SAM. The generated pulse train has a repetition rate of 113.6 kHz and an average output power of 37 mW. Our results show that the BP-SAMs could have excellent prospective for ultrafast photonics applications.

Jie Ma;Shunbin Lu;Zhinan Guo;Xiaodong Xu;Han Zhang;定元 汤;滇元 范

Optics Express

2015

We demonstrate experimentally that few atomic layer graphene possesses ultrafast, super broadband saturable absorption, which can be exploited to passive mode lock fiber lasers of different operation wavelengths. Passive mode locking performance of an erbium-doped fiber laser operating at the 1.55μm and an ytterbium-doped fiber laser operating at the 1.06μm with a graphene saturable absorber mirror has been experimentally demonstrated, and wavelength tuneable solitons, vector solitons, as well as the bound state of solitons have been observed.

定元 汤;H. Zhang;Q. L. Bao;K. P. Loh

2011

Highly transparent Yb³⁺ doped Y₂O₃ (Yb³⁺: Y₂O₃) ceramics was fabricated by a solid-state reaction method using ZrO₂ and La₂O₃ as additives. The morphology of the prepared powder was investigated and the phase of the sintered Yb³⁺: Y₂O₃ ceramics sample was identified. The microstructure, transmittance spectrum, Vickers hardness and fracture toughness for the as-sintered Yb³⁺: Y₂O₃ ceramics were measured. The average grain size was about 9.11 μm and the transmittance at the wavelength of 2000 nm was about 82.0%, which was 99% of the theoretical value. ZrO₂ and La₂O₃ were useful additives for highly transparent Yb³⁺: Y₂O₃ ceramics fabrication and mechanical properties improvement.

Kaijie Ning;Jun Wang;Dewei Luo;Jie Ma;Jian Zhang;Zhi Li Dong;Ling Bing Kong;定元 汤

Optical Materials

2015-12

The design features and advantages of a discrete wavelength tunable laser, demonstrated by microelectromechanical systems (MEMS) technology, were analyzed. A semiconductor laser, a single-mode optical fiber and a MEMS mirror were integrated onto a single chip to obtain the laser system. A single longitudinal mode was maintained while tuning the wavelength of a monolithic MEMS tunable laser by discrete steps to discrete values. The wide tuning range, fast tuning speed, high wavelength and easy monolithic integration were presented as the benefits from DWT lasers. It was found that the laser was tuned at a tuning range of 13.5 nm and a sweeping speed of about 1 ms.

X. M. Zhang;A. Q. Liu;定元 汤;C. Lu

Applied Physics Letters

2004-1-19

We experimentally observed two forms of subsideband generation in the soliton spectrum of a passively mode-locked fiber soliton ring laser. We found that the different forms of subsideband generation are related to the different strengths of the saturable absorption in the laser cavity. Analyzing featuring of the subsideband generations, we show that they are both modulational-instability lasings of the dispersive waves in the laser.

定元 汤;S. Fleming;W. S. Man;H. Y. Tam;M. S. Demokan

Journal of the Optical Society of America B: Optical Physics

2001-10

Dynamics of the intensity and optical field amplitude of a coherently pumped far-infrared NH₃-laser are measured and characterized. The experimental findings in certain parameter ranges closely follow the dynamics of the Lorenz model and its generalization for laser systems. Similarities and some specific differences are found in geometrical or statistical characterizations of the attractors. The experimental results are also consistent with the results of a model of optically pumped three-level lasers which takes into account the presence of a multiplicity of velocity groups as well as three-level coherence effects. For a certain region in parameter space, this far more complex model with a much larger phase space produces results similar to the dynamics of the Lorenz model. The model also provides explanations of differences between the experimental results and results from the Lorenz model.

C. O. Weiss;R. Vilaseca;N. B. Abraham;R. Corbalán;E. Roldán;G. J. de Valcárcel;J. Pujol;U. Hübner;定元 汤

Applied Physics B: Lasers and Optics

1995-9

We report measurements on the phase dynamics of a detuned single mode laser which has in the past shown correspondence to the complex Lorenz equation. The corresponding ranges of periodic pulsing, of detuned chaos and of windows within the chaotic domain are investigated.

定元 汤;C. O. Weiss

Applied Physics B: Photophysics and Laser Chemistry

1992-8

The nonlinear response of a chaotic system to a chaotic variation in a system parameter is investigated experimentally. Clear experimental evidence of frequency entrainment of the chaotic oscillations is observed. We show that analogous to the frequency locking between coupled periodic oscillations, this effect is generic for coupled chaotic systems.

定元 汤;R. Dykstra;M. W. Hamilton;N. R. Heckenberg

Physical Review E

1998

A type of bound states of solitons in a passively mode-locked fiber soliton laser was experimentally observed. The observed bound states of solitons are characterized as being very stable, and have discrete, fixed soliton separations. Comparing the pulse separation of the bound solitons with that of the individual soliton pulse duration, it was shown that the formation of the observed bound solitons is due to a direct interaction between the solitons in the laser.

定元 汤;W. S. Man;H. Y. Tam;P. D. Drummond

Physical Review A

2001-9

Modulation instability is the well-known tendency in anomalous dispersion fibres for small variations in an almost constant power level to grow exponentially. For an erbium doped fibre soliton laser, although it operates in the anomalous dispersion regime of the fibre used and a strong internal gain exits in it, because a soliton pulse is inherently stable against modulation instability, normally no modulation instability can be observed. In this paper we report on an experimental observation of modulation instability in a passively mode-locked fibre soliton ring laser. We show that due to modulation instability, dispersive waves of the laser can become unstable and consequently result in the generation of new spectral components in the soliton spectrum.

定元 汤;P. D. Drummond;W. S. Man;H. Y. Tam;M. S. Demokan

1999