Debye Institute for Nanomaterials Science, University of Utrecht, PO Box 80.000, 3508 TA, Utrecht, The Netherlands.
Nanoscale. 2011 Jul;3(7):2783-800. doi: 10.1039/c1nr00013f. Epub 2011 May 6.
The pathway towards the realization of optical solid-state lasers was gradual and slow. After Einstein's paper on absorption and stimulated emission of light in 1917 it took until 1960 for the first solid state laser device to see the light. Not much later, the first semiconductor laser was demonstrated and lasing in the near UV spectral range from ZnO was reported as early as 1966. The research on the optical properties of ZnO showed a remarkable revival since 1995 with the demonstration of room temperature lasing, which was further enhanced by the first report of lasing by a single nanowire in 2001. Since then, the research focussed increasingly on one-dimensional nanowires of ZnO. We start this review with a brief description of the opto-electronic properties of ZnO that are related to the wurtzite crystal structure. How these properties are modified by the nanowire geometry is discussed in the subsequent sections, in which we present the confined photon and/or polariton modes and how these can be investigated experimentally. Next, we review experimental studies of laser emission from single ZnO nanowires under different experimental conditions. We emphasize the special features resulting from the sub-wavelength dimensions by presenting our results on single ZnO nanowires lying on a substrate. At present, the mechanism of lasing in ZnO (nanowires) is the subject of a strong debate that is considered at the end of this review.
实现光学固态激光器的途径是逐步和缓慢的。在爱因斯坦于 1917 年发表关于光的吸收和受激辐射的论文之后，直到 1960 年才出现了第一个固态激光器件。不久之后，第一个半导体激光器被演示出来，并且早在 1966 年就报道了 ZnO 的近紫外光谱范围内的激光激射。自 1995 年以来，随着室温激光激射的演示，以及 2001 年第一个单根纳米线激光激射的报道，ZnO 的光学性质研究出现了显著的复兴。此后，研究越来越集中在 ZnO 的一维纳米线上。我们从 ZnO 的光电性质的简要描述开始，这些性质与纤锌矿晶体结构有关。在下一节中，我们将讨论纳米线几何形状如何对这些性质进行修饰，我们将介绍限制光子和/或极化激元模式以及如何通过实验来研究这些模式。接下来，我们将回顾在不同实验条件下，单个 ZnO 纳米线的激光发射的实验研究。我们强调了亚波长尺寸的特殊性质，通过展示我们在置于基底上的单个 ZnO 纳米线上的结果。目前，ZnO（纳米线）中的激光激射机制是一个激烈争论的主题，我们将在本综述的最后对其进行考虑。
