Multi-photon-pumped stimulated emission from ZnO nanowires: A time-resolved study

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• 作者：Kui Han ; ^{han6409@263.net} ; Juanjuan Wang ; Yifeng Sheng ; Faliang Ju ; Xiaopeng Sheng ; Yuxi Wu ; Gang Tang
• 关键词：ZnO nanowire ; Time-resolved photoluminescence ; Multi-photon absorption
• 刊名：Physics Letters A
• 出版年：2012
• 出版时间：7 May, 2012
• 年：2012
• 卷：376
• 期：23
• 页码：1871-1874
• 全文大小：483 K

文摘

In this work, we study temporal evolution of multi-photon-pumped stimulated emission from ZnO nanowires. In addition to second harmonic generation, ultraviolet stimulated emission is observed in ZnO nanowires under femtosecond pulse excitation at 800 nm. Sharp emission peaks appear when excitation flux reaches a threshold of 80 mJ/cm², which can be interpreted as lasing action in self-formed nanowire microcavities. Temporal evolution of the emission captured by Kerr shutter technique shows strong excitation-power dependence. The dynamic trace of stimulated emission exhibits a fast decay with a lifetime about 4.5 ps at intermediate excitation (?00 mJ/cm²) and a lifetime about 2 ps at high excitation (>160 mJ/cm²). The difference in the lifetime can be attributed to different gain mechanisms related to excitonic interaction and electron-hole plasma, respectively.