We demonstrate a simple,compact and low-cost mode-locked erbium-doped fiber laser(EDFL)using a single-wall carbon nanotube(SWCNT)poly-ethylene oxide(PEO)composite as a passive saturable absorber(SA).The composite with...We demonstrate a simple,compact and low-cost mode-locked erbium-doped fiber laser(EDFL)using a single-wall carbon nanotube(SWCNT)poly-ethylene oxide(PEO)composite as a passive saturable absorber(SA).The composite with an SWCNT concentration of 18wt%is prepared by mixing the SWCNT homogeneous solution with a diluted PEO polymer solution.A droplet of the polymer composite is applied on the fiber ferrule end,which is then mated to another clean ferrule connector to construct an SA.The SA is then integrated into the laser system to self-start stable mode locking at 1557 nm without employing a polarization controller.The EDFL generates a stable soliton pulse train with a duration of 0.81 ps,repetition rate of 44 MHz and average output power of 92.4μW at a 980 nm pump power of 26.8 mW.The soliton laser starts to lase at a pump power threshold of 14.6 mW.展开更多
The van der Waals force originates from the electromagnetic interaction between quantum fluctuationinduced charges. It is a ubiquitous but subtle force which plays an important role and has a wide range of application...The van der Waals force originates from the electromagnetic interaction between quantum fluctuationinduced charges. It is a ubiquitous but subtle force which plays an important role and has a wide range of applications in surface related phenomena like adhesion, friction,and colloidal stability. Calculating the van der Waals force between closely spaced metallic nanoparticles is very challenging due to the strong concentration of electromagnetic fields at the nanometric gap. Especially, at such a small length scale, the macroscopic description of the dielectric properties no longer suffices. The diffuse nonlocal nature of the induced surface electrons which are smeared out near the boundary has to be considered. Here,we review the recent progress on using three-dimensional transformation optics to study the van der Waals forces between closely spaced nanostructures. Through mapping a seemingly asymmetric system to a more symmetric counterpart, transformation optics enables us to look into the behavior of van der Waals forces at extreme length scales,where the effect of nonlocality is found to dramatically weaken the van der Waals interactions.展开更多
基金the University of Malaya PPP under Grant No PV030/2012Athe University of Malaya Research Grant under Grant No RG144-12AET.
文摘We demonstrate a simple,compact and low-cost mode-locked erbium-doped fiber laser(EDFL)using a single-wall carbon nanotube(SWCNT)poly-ethylene oxide(PEO)composite as a passive saturable absorber(SA).The composite with an SWCNT concentration of 18wt%is prepared by mixing the SWCNT homogeneous solution with a diluted PEO polymer solution.A droplet of the polymer composite is applied on the fiber ferrule end,which is then mated to another clean ferrule connector to construct an SA.The SA is then integrated into the laser system to self-start stable mode locking at 1557 nm without employing a polarization controller.The EDFL generates a stable soliton pulse train with a duration of 0.81 ps,repetition rate of 44 MHz and average output power of 92.4μW at a 980 nm pump power of 26.8 mW.The soliton laser starts to lase at a pump power threshold of 14.6 mW.
基金partially supported by the Gordon and Betty Moore Foundation (J. B. P.)the Royal Commission for the Exhibition of 1851 (R. Z.)+2 种基金the Leverhulme Trust (Y. L. and J. B. P.)the MOE Ac RF Tier 2 (Y. L.)the Program Grant (11235150003) from NTU-A*STAR Silicon Technologies Centre of Excellence (Y. L.)
文摘The van der Waals force originates from the electromagnetic interaction between quantum fluctuationinduced charges. It is a ubiquitous but subtle force which plays an important role and has a wide range of applications in surface related phenomena like adhesion, friction,and colloidal stability. Calculating the van der Waals force between closely spaced metallic nanoparticles is very challenging due to the strong concentration of electromagnetic fields at the nanometric gap. Especially, at such a small length scale, the macroscopic description of the dielectric properties no longer suffices. The diffuse nonlocal nature of the induced surface electrons which are smeared out near the boundary has to be considered. Here,we review the recent progress on using three-dimensional transformation optics to study the van der Waals forces between closely spaced nanostructures. Through mapping a seemingly asymmetric system to a more symmetric counterpart, transformation optics enables us to look into the behavior of van der Waals forces at extreme length scales,where the effect of nonlocality is found to dramatically weaken the van der Waals interactions.
