UV radiation of powdered ZnO pumped by nanosecond pulses
UV radiation of powdered ZnO pumped by nanosecond pulses
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纳秒脉冲泵浦的氧化锌粉末的紫外辐射
DOI：
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发表时间：
2005
期刊：
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通讯作者：
L. N. Demianets
中科院分区：
文献类型：
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作者：
V. Markushev;M. Ryzhkov;C. Briskina;H. Cao;L. Zadorozhnaya;L. Li;E. I. Gevargizov;L. N. Demianets
由于氧化锌中自发复合紫外辐射的本征寿命小于~ 200ps，因此用纳秒持续时间的泵浦脉冲获得氧化锌粉末的受激紫外辐射是一个有意义的研究方向。这将阐明在无序介质中准连续激光辐射的可能性。同时，该效应为研制窄光谱短持续时间阴极发光屏开辟了道路。对氧化锌粉末和一些无序薄膜的紫外辐射光谱进行了研究。用两级Nd: yag激光器（λ= 355nm）的三次谐波泵浦样品，脉冲持续时间为10ns。泵送脉冲的最大能量密度约为160 mJ/cm2。在300K和77K处记录了自发发射光谱。对于一些粉末样品，我们在300K下实现了激光。抽运能量密度的阈值比皮秒抽运的阈值高了大约两个数量级。对不同样品的激光特性进行了论证和讨论。在300K紫外波段，ZnO薄膜的光谱最大值位于~382 nm，而ZnO粉末的光谱最大值位于~389 nm。此外，随着泵浦功率的增加，薄膜中紫外波段的长波长部分变宽。
Since the intrinsic lifetime of spontaneous recombination UV radiation in zinc oxide amounts less than ~200 ps it is of interest to obtain stimulated UV radiation of powdered ZnO with pumping pulses of nanosecond duration. This will clarify the possibility of quasi-continuous laser radiation in disordered media. At the same time this effect can open the way for working out a cathodoluminescent screen with narrow spectrum and short persistence time. Investigations of UV radiation spectra of powdered zinc oxide and some disordered films were conducted. The samples were pumped by 3-rd harmonics of the two-stage Nd:YAG-laser (λ=355 nm) with pulse duration ~10 ns. Maximum density of energy of pumping pulses was about 160 mJ/cm2. Spectra of spontaneous emission were registered at 300K and 77K. With some of our powdered samples we achieved lasing at 300K. The threshold values of pumping energy density occurred to be higher than that under picosecond pumping approximately for two orders of magnitude. Peculiarities of different samples lasing are demonstrated and discussed. In spectra of the ZnO films investigated at 300K UV band maximum is situated at ~382 nm, while in powders of ZnO this maximum was located at ~389 nm. Besides, in the films the long-wavelength part of the UV band broadens with increase of pumping power.