Song Jae Kyu, Szarko Jodi M, Leone Stephen R, Li Shihong, Zhao Yiping
Department of Chemistry, and Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA.
J Phys Chem B. 2005 Aug 25;109(33):15749-53. doi: 10.1021/jp051883p.
The ultrafast lasing dynamics of single zinc oxide nanotetrapods and nanowires are investigated by two-color femtosecond excitation/optical injection spectroscopy. The transient spectral gain induced by time-delayed optical injection pulses (400 nm) is used to investigate the spectrally and temporally resolved lasing properties in a single tetrapod or nanowire laser excited by 267-nm pulses. The lasing output pulse exhibits a faster lasing decay time than the carrier decays due to the superlinear dependence of the lasing on the carrier density. Lasing at the low-energy side of the gain bandwidth (392 nm) has a full width at half maximum (fwhm) for stimulated emission of 1.7 ps. Lasing at 390 nm, the high-energy side of the gain bandwidth, has a fwhm of 2.1 ps for a single example nanowire. The change in lasing dynamics as a function of wavelength is affected by band gap renormalization, since lasing in the electron-hole plasma regime depends not only on the carrier density but also on the band gap shift with carrier density.
通过双色飞秒激发/光注入光谱研究了单个氧化锌纳米四脚体和纳米线的超快激光动力学。利用延迟光注入脉冲（400纳米）诱导的瞬态光谱增益，来研究由267纳米脉冲激发的单个四脚体或纳米线激光器中的光谱和时间分辨激光特性。由于激光对载流子密度的超线性依赖，激光输出脉冲的激光衰减时间比载流子衰减更快。在增益带宽（392纳米）低能量侧的激光，其受激发射的半高全宽（fwhm）为1.7皮秒。对于单个示例纳米线，在增益带宽高能量侧390纳米处的激光，其fwhm为2.1皮秒。由于在电子 - 空穴等离子体区域的激光不仅取决于载流子密度，还取决于带隙随载流子密度的变化，所以激光动力学随波长的变化受带隙重整化影响。
