氟化钙晶体微腔相比玻璃材料微腔,具有吸收系数小、缺陷少、纯度高、对周围环境湿度不敏感的优势,在微波光子学、陀螺仪和非线性光学等领域具有潜在的应用价值。通过超精密加工技术制备了回转椭球体氟化钙毫米晶体微腔。研发了一套精密加工系统来制备这种微腔,所制得的微腔形状为回转椭球体,微腔结构边缘表面粗糙度低至1.97 nm。使用光纤锥波导与氟化钙微腔实现了高效耦合,此耦合系统展现了高达~10 ⁸的超高品质因子Q值和低至约0.03 nm的自由光谱范围。这些结果证明了针对氟化钙微腔的加工手段具有重要意义,将大大促进其应用。氟化钙微腔的特性也证明了它在光学滤波器、腔量子动力学、非线性光学和陀螺仪等应用中的潜力。

Compared with glass microcavity, a calcium fluoride (CaF₂) crystalline microcavity has the advantages of small absorption coefficient, fewer defects, higher purity, and being insensitive to ambient humidity. It has potential applications in microwave photonics, gyroscopes, and nonlinear optics. In this paper, a spheroid CaF₂ millimeter crystalline microcavity is fabricated by the ultra-precision machining technology. To fabricate such a microcavity, a home-made precision machining system is developed. The shape of the fabricated microcavity is a spheroid, and the surface roughness of the edge of the microcavity is as low as 1.97 nm. Efficient coupling between the tapered fiber waveguide and the CaF₂ crystalline microcavity is achieved. The coupling system exhibits an ultra-high-quality (Q) factor up to ~10 ⁸ and a free-spectral-range as low as ~0.03 nm. These results demonstrate that the fabrication method for the CaF₂ crystalline microcavity is significant, and can promote its applications. The characteristics of CaF₂ crystalline microcavity also prove its potential in optical filter, cavity quantum electrodynamics, nonlinear optics, and optical gyroscope.