Li Huiqi, Wang Zhaocong, Wang Lei, Tan Yang, Chen Feng
School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan, China.
Light Sci Appl. 2023 Sep 12;12(1):223. doi: 10.1038/s41377-023-01264-6.
Whispering-gallery-mode microcavity lasers possess remarkable characteristics such as high Q factors and compact geometries, making them an essential element in the evolution of microlasers. However, solid-state whispering-gallery-mode lasers have previously suffered from low output power and limited optical conversion efficiency, hindering their applications. Here, we present the achievement of milliwatt laser emissions at a wavelength of 1.06 µm from a solid-state whispering-gallery-mode laser. To accomplish this, we construct a whispering-gallery-mode microcavity (with a diameter of 30 µm) using a crystalline Nd: YAG thin film obtained through carbon-implantation enhanced etching of a Nd: YAG crystal. This microcavity laser demonstrates a maximum output power of 1.12 mW and an optical conversion efficiency of 12.4%. Moreover, our unique eccentric microcavity design enables efficient coupling of free-space pump light, facilitating integration with a waveguide. This integration allowed for single-wavelength laser emission from the waveguide, achieving an output power of 0.5 mW and an optical conversion efficiency of 6.18%. Our work opens up new possibilities for advancing solid-state whispering-gallery-mode lasers, providing a viable option for compact photonic sources.
回音壁模式微腔激光器具有诸如高品质因数和紧凑几何结构等显著特性，使其成为微激光器发展中的关键元件。然而，固态回音壁模式激光器此前一直存在输出功率低和光学转换效率有限的问题，这阻碍了它们的应用。在此，我们展示了从固态回音壁模式激光器实现波长为1.06 µm的毫瓦级激光发射。为实现这一目标，我们使用通过对Nd:YAG晶体进行碳离子注入增强刻蚀获得的晶体Nd:YAG薄膜构建了一个回音壁模式微腔（直径为30 µm）。这种微腔激光器展示出1.12 mW的最大输出功率和12.4%的光学转换效率。此外，我们独特的偏心微腔设计能够实现自由空间泵浦光的高效耦合，便于与波导集成。这种集成使得从波导实现单波长激光发射，输出功率达到0.5 mW，光学转换效率为6.18%。我们的工作为推进固态回音壁模式激光器开辟了新的可能性，为紧凑型光子源提供了一个可行的选择。
