We present a laser-diode-pumped passively mode-locked femtosecond disordered crystal laser by using Nd：CaGdAI04 （Nd：CGA） as the gain medium. With a pair of SF6 prisms to control the dispersion compensation, laser ...We present a laser-diode-pumped passively mode-locked femtosecond disordered crystal laser by using Nd：CaGdAI04 （Nd：CGA） as the gain medium. With a pair of SF6 prisms to control the dispersion compensation, laser pulses as short as 850fs at 1079nm are obtained with a repetition rate of 124.6 MHz. The measured threshold pump power is 1.45 W. A maximum average output power of 122mW is obtained under the pump power of 5.9 W. These results show that Nd：CGA could be a promising laser medium for generating femtosecond ultrashort pulse at about 1 μm.展开更多
Thermally driven diffusive motion of a particle underlies many physical and biological processes. In the presence of traps and obstacles, the spread of the particle is substantially impeded, leading to subdiffusive sc...Thermally driven diffusive motion of a particle underlies many physical and biological processes. In the presence of traps and obstacles, the spread of the particle is substantially impeded, leading to subdiffusive scaling at long times. The statistical mechanical treatment of diffusion in a disordered environment is often quite involved. In this short review, we present a simple and unified view of the many quantitative results on anomalous diffusion in the literature, including the scaling of the diffusion front and the mean first-passage time. Varioust analytic calculations and physical arguments are examined to highlight the role of dimensionality, energy landscape, and rare events in affecting the particle trajectory statistics. The general understanding that emerges will aid the interpretation of relevant experimental and simulation results.展开更多
The transmission spectra of a TiO2-silicone oil suspension in an increasing external electric field are studied. As the electric field increases, the structure of the suspension changes from a disordered one to an ord...The transmission spectra of a TiO2-silicone oil suspension in an increasing external electric field are studied. As the electric field increases, the structure of the suspension changes from a disordered one to an ordered one. Interestingly, the transmission spectra blueshift in this structure-ordering process. Furthermore, the relative transmission spectra exhibit Fano-like asymmetric line shapes. The deviation ratio of each asymmetric line shape increases monotonously as the disorder of the suspension decreases. We suggest that this blueshift phenomenon can be used to characterize the disorder strength of three- dimensional systems.展开更多
基金Supported by the National Key Basic Research Program of China under Grant No 2013CB922402the International Joint Research Program,and the National Natural Science Foundation of China under Grant Nos 61210017 and 11434016
文摘We present a laser-diode-pumped passively mode-locked femtosecond disordered crystal laser by using Nd：CaGdAI04 （Nd：CGA） as the gain medium. With a pair of SF6 prisms to control the dispersion compensation, laser pulses as short as 850fs at 1079nm are obtained with a repetition rate of 124.6 MHz. The measured threshold pump power is 1.45 W. A maximum average output power of 122mW is obtained under the pump power of 5.9 W. These results show that Nd：CGA could be a promising laser medium for generating femtosecond ultrashort pulse at about 1 μm.
基金supported by the National Natural Science Foundation of China (Grant No. 11175013)the Research Grants Council of the Hong Kong Special Administrative Region,China (Grant No. N HKBU 213/10)
文摘Thermally driven diffusive motion of a particle underlies many physical and biological processes. In the presence of traps and obstacles, the spread of the particle is substantially impeded, leading to subdiffusive scaling at long times. The statistical mechanical treatment of diffusion in a disordered environment is often quite involved. In this short review, we present a simple and unified view of the many quantitative results on anomalous diffusion in the literature, including the scaling of the diffusion front and the mean first-passage time. Varioust analytic calculations and physical arguments are examined to highlight the role of dimensionality, energy landscape, and rare events in affecting the particle trajectory statistics. The general understanding that emerges will aid the interpretation of relevant experimental and simulation results.
文摘The transmission spectra of a TiO2-silicone oil suspension in an increasing external electric field are studied. As the electric field increases, the structure of the suspension changes from a disordered one to an ordered one. Interestingly, the transmission spectra blueshift in this structure-ordering process. Furthermore, the relative transmission spectra exhibit Fano-like asymmetric line shapes. The deviation ratio of each asymmetric line shape increases monotonously as the disorder of the suspension decreases. We suggest that this blueshift phenomenon can be used to characterize the disorder strength of three- dimensional systems.
