ZnO粉末中无序激射现象时间分辨的研究

Time-resolved study of the random lasing in ZnO powder

采用抽运 -探测时间分辨方法实验研究了半导体材料ZnO纳米颗粒粉末中的无序激射现象 .在 2 6 7nm激光的抽运下 ,通过精确控制抽运光的能量和样品表面的抽运面积 ,获得了宽度小于 1nm的单模无序激射光谱和多峰的多模无序激射光谱 .时间分辨的抽运 -探测结果显示 ,此时样品的上能级寿命仅为几个皮秒 。

In this letter, we investigated random lasing phenomenon in ZnO powder using the pump-probe technique. Under 267nm laser pumping, supernarrow single-mode emission and multi-mode emission were observed by precisely controlling the pumping intensity and the excitation beam size on the sample. The supernarrow emission peaks are much narrower than the normal luminescence and ASE spectra. The time-resolved pump-probe measurement shows that the lifetime of the emission state above the lasing threshold is only a few picoseconds which demonstrates that the formation of supernarrow random lasing bandwidth is due to stimulated emission.