Department of Physics, Engineering Physics & Astronomy, Queen's University, Kingston, Ontario, K7L 3N6 Canada.
Phys Rev Lett. 2010 Jan 8;104(1):017401. doi: 10.1103/PhysRevLett.104.017401.
Single air-suspended carbon nanotubes (length 2-5 microm) exhibit high optical quantum efficiency (7-20%) for low intensity resonant pumping. Under ultrafast excitation (150 fs), emission dramatically saturates at very low exciton numbers (2-6), which is attributed to highly efficient exciton-exciton annihilation over micron-length scales. Similar saturation behavior for 4 ps pulse excitation shows nonlinear absorption is not a contributing factor. The absorption cross sections (0.6-1.8x10(-17) cm2/atom) are determined by fitting to a stochastic model for exciton dynamics.
单根悬空的碳纳米管（长度 2-5 微米）在低强度共振激发下表现出很高的光学量子效率（7-20%）。在超快激发（150fs）下，在非常低的激子数（2-6）下，发射急剧饱和，这归因于在微米长度尺度上高效的激子-激子湮灭。对于 4ps 脉冲激发，相似的饱和行为表明非线性吸收不是一个贡献因素。吸收截面（0.6-1.8x10(-17) cm2/atom）通过对激子动力学的随机模型拟合来确定。
