Phonon-Assisted Lasing in ZnO Microwires at Room Temperature
Phonon-Assisted Lasing in ZnO Microwires at Room Temperature
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DOI：
10.1063/1.4902898
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发表时间：
2014-10
期刊：
影响因子：
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通讯作者：
T. Michalsky;M. Wille;C. Dietrich;R. Roder;C. Ronning;R. Schmidt‐Grund;M. Grundmann
中科院分区：
文献类型：
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作者：
T. Michalsky;M. Wille;C. Dietrich;R. Roder;C. Ronning;R. Schmidt‐Grund;M. Grundmann
我们报道了ZnO微线中声子辅助的回音壁模式（WGM）激光。对于基于低增益声子散射过程的WGM激光器，具有尖角和光滑端面的高质量谐振腔是先决条件。当激发阈值功率P_{Th}$为100 kW/cm ^2 $时，自由激子在两个纵向光学声子发射下的复合提供了足够的增益以克服微谐振腔中的所有损耗并导致激光振荡。这种阈值行为伴随着远场和近场发射模式的明显变化，揭示了激光模式的WGM相关性质。光谱演化以及集成的光致发光强度与激发功率的特性行为明确地证明了激光器的操作。偏振分辨的测量表明，激光发射线偏振垂直于微丝轴（TE）。
We report on room temperature phonon-assisted whispering gallery mode (WGM) lasing in ZnO microwires. For WGM laser action on the basis of the low gain phonon scattering process high quality resonators with sharp corners and smooth facets are prerequisite. Above the excitation threshold power $P_{\textit{Th}}$ of typically $100\,kW/cm^2$, the recombination of free excitons under emission of two longitudinal optical phonons provides sufficient gain to overcome all losses in the microresonator and to result in laser oscillation. This threshold behavior is accompanied by a distinct change of the far and near field emission patterns, revealing the WGM related nature of the lasing modes. The spectral evolution as well as the characteristic behavior of the integrated photoluminescence intensity versus the excitation power unambiguously prove laser operation. Polarization-resolved measurements show that the laser emission is linear polarized perpendicular to the microwire axis (TE).