Modeled with a three-level-atom appropriate to 980 nm pumped amplifiers,analytical solutions have been deduced for the rate equations of erbium-doped fiber amplifiers.Various key parameters of the amplifiers have been...Modeled with a three-level-atom appropriate to 980 nm pumped amplifiers,analytical solutions have been deduced for the rate equations of erbium-doped fiber amplifiers.Various key parameters of the amplifiers have been specified.展开更多
Nanopumps conducting fluids directionally through nanopores and nanochannels have attracted considerable interest for their potential applications in nanofiltration, water purification, and hydroelectric power generat...Nanopumps conducting fluids directionally through nanopores and nanochannels have attracted considerable interest for their potential applications in nanofiltration, water purification, and hydroelectric power generation Here, we demonstrate by molecular dynamics simulations that an excited vibrating carbon nanotube （CNT） cantilever can act as an efficient and simple nanopump. Water molecules inside the vibrating cantilever are driven by centrifugal forces and can undergo a continuous flow from the fixed to free ends of the CNT. Further extensive simulations show that the pumping function holds good not only for a single-file water chain in a narrow （6,6） CNT, but also for bulk-like water columns inside wider CNTs, and that the water flux increases monotonically with increasing diameter of the nanotube.展开更多
We employ optical pump-terahertz probe spectroscopy to investigate the composition-dependent photoconductivity in ternary CdSxSel_x nanobelts. The observed carrier dynamics of CdS nanobelts display much shorter lifeti...We employ optical pump-terahertz probe spectroscopy to investigate the composition-dependent photoconductivity in ternary CdSxSel_x nanobelts. The observed carrier dynamics of CdS nanobelts display much shorter lifetime than those of ternary CdSKSel_K nanobelts. This indicates the implementation of CdS nanobelts as ultrafast switching devices with a switching speed potentially up to 46.7 GHz. Surprisingly, ternary CdS,-Sel_x nanobelts are found to exhibit much higher photoconductivity than binary CdS and CdSe. This is attributed to the higher photocarrier densities in ternary compounds. In addition, the presence of Se in samples resulted in prominent CdSe-like transverse optical （TO） phonon modes due to electron-phonon interactions. The strength of this mode shows a large drop upon photoexcitation but recovers gradually with time. These results demonstrated that growth of ternary nanostructures can be utilized to alleviate the high surface defect density in nanostructures and improve their photoconductivity.展开更多
In this paper, we study an optomechanical device consisting of a Fabry-P6rot cavity with two dielectric nanospheres trapped near the cavity mirrors by an external driving laser. In the condition where the distances be...In this paper, we study an optomechanical device consisting of a Fabry-P6rot cavity with two dielectric nanospheres trapped near the cavity mirrors by an external driving laser. In the condition where the distances between the nanospheres and cavity mirrors are small enough, the Casimir force helps the optomechanical coupling to induce a steady-state optomechanical entanglement of the mechanical and optical modes in a certain regime of parameters. We investigate in detail the dependence of the steady- state optomechanical entanglement on external control parameters of the system, i.e., the effective detuning, the pump powers of the cavity, the cavity decay rate and the wavelength of the driving field. It is found that the large steady-state optomechanical entanglement, i.e. EN = 5.76, can be generated with experimentally feasible parameters, i.e. the pump power P = 18.2 μW, the cavity decay rate K = 0.5 MHz and the wavelength of the laser AL=1064 nm, which should be checked by optical measurement.展开更多
An all-solid-state Pr:KY3F10(Pr:KYF) laser pumped by blue laser(471 nm) has been demonstrated.With the incident pump power of 2.6 W,the maximum output power at 610 nm is 213 mW.Moreover,the intracavity second-harmonic...An all-solid-state Pr:KY3F10(Pr:KYF) laser pumped by blue laser(471 nm) has been demonstrated.With the incident pump power of 2.6 W,the maximum output power at 610 nm is 213 mW.Moreover,the intracavity second-harmonic generation(SHG) is also achieved with the maximum ultraviolet(UV) power at 305 nm of 11 mW by using a β-BaB2O4(BBO) nonlinear crystal.展开更多
文摘Modeled with a three-level-atom appropriate to 980 nm pumped amplifiers,analytical solutions have been deduced for the rate equations of erbium-doped fiber amplifiers.Various key parameters of the amplifiers have been specified.
基金This work was supported by the 973 Program （No. 2007CB936204）, National and Jiangsu Province National Science Foundation （NSF） （Nos. 10732040, 10802037, 30970557, and BK2008042） of China, and Nanjing University of Aeronautics and Astronautics Funds （No. BCXJ08-02）. The authors thank Drs. Yitao Dai, Chun Tang, and Zhuhua Zhang for helpful discussions.
文摘Nanopumps conducting fluids directionally through nanopores and nanochannels have attracted considerable interest for their potential applications in nanofiltration, water purification, and hydroelectric power generation Here, we demonstrate by molecular dynamics simulations that an excited vibrating carbon nanotube （CNT） cantilever can act as an efficient and simple nanopump. Water molecules inside the vibrating cantilever are driven by centrifugal forces and can undergo a continuous flow from the fixed to free ends of the CNT. Further extensive simulations show that the pumping function holds good not only for a single-file water chain in a narrow （6,6） CNT, but also for bulk-like water columns inside wider CNTs, and that the water flux increases monotonically with increasing diameter of the nanotube.
文摘We employ optical pump-terahertz probe spectroscopy to investigate the composition-dependent photoconductivity in ternary CdSxSel_x nanobelts. The observed carrier dynamics of CdS nanobelts display much shorter lifetime than those of ternary CdSKSel_K nanobelts. This indicates the implementation of CdS nanobelts as ultrafast switching devices with a switching speed potentially up to 46.7 GHz. Surprisingly, ternary CdS,-Sel_x nanobelts are found to exhibit much higher photoconductivity than binary CdS and CdSe. This is attributed to the higher photocarrier densities in ternary compounds. In addition, the presence of Se in samples resulted in prominent CdSe-like transverse optical （TO） phonon modes due to electron-phonon interactions. The strength of this mode shows a large drop upon photoexcitation but recovers gradually with time. These results demonstrated that growth of ternary nanostructures can be utilized to alleviate the high surface defect density in nanostructures and improve their photoconductivity.
基金supported by the National Basic Research Program of China(Grant Nos.2011CB922203,2012CB921603 and 2012CB922104)the National Natural Science Foundation of China(Grant Nos.11304010,11174027 and 11375093)
文摘In this paper, we study an optomechanical device consisting of a Fabry-P6rot cavity with two dielectric nanospheres trapped near the cavity mirrors by an external driving laser. In the condition where the distances between the nanospheres and cavity mirrors are small enough, the Casimir force helps the optomechanical coupling to induce a steady-state optomechanical entanglement of the mechanical and optical modes in a certain regime of parameters. We investigate in detail the dependence of the steady- state optomechanical entanglement on external control parameters of the system, i.e., the effective detuning, the pump powers of the cavity, the cavity decay rate and the wavelength of the driving field. It is found that the large steady-state optomechanical entanglement, i.e. EN = 5.76, can be generated with experimentally feasible parameters, i.e. the pump power P = 18.2 μW, the cavity decay rate K = 0.5 MHz and the wavelength of the laser AL=1064 nm, which should be checked by optical measurement.
基金supported by the National Natural Science Foundation of China (No.61108029)
文摘An all-solid-state Pr:KY3F10(Pr:KYF) laser pumped by blue laser(471 nm) has been demonstrated.With the incident pump power of 2.6 W,the maximum output power at 610 nm is 213 mW.Moreover,the intracavity second-harmonic generation(SHG) is also achieved with the maximum ultraviolet(UV) power at 305 nm of 11 mW by using a β-BaB2O4(BBO) nonlinear crystal.
