基于微毛细管折射率传感器的优化研究

Optimization Research on Refractometric Sensor Based on Microcapillary

将4阶回音壁谐振模式(WGM)应用于折射率传感器的检测中。实验中以壁厚为4.8μm的微毛细管构建折射率传感器,验证了不同WGM的传感器灵敏度有显著差异。实验获得的最高灵敏度达到48.74nm/RIU(折射率单位),对应的探测极限达6.2×10-6 RIU。通过与模拟结果对比,清晰地识别出4阶WGM共振峰,并且4阶WGM在传感灵敏度方面有明显的优势。此外,分析了环境温度的扰动对不同径向阶数WGM共振波长的影响,发现与其他低阶模相比4阶WGM表现出低温度响应的优势。为实现实用的高灵敏度、抗热噪声折射率传感器提供了理论和实验基础。

The application of 4th radial order whispering-gallery mode （WGM） on refractometric sensor is investigated. A microcapillary resonator with 4.8 μm wall thickness is researched in experiment and the sensitivity difference among different modes is observed. The highest sensitivity of 48.74 nm/RIU （refractive index unit） and detection limit of 6.2 × 10^-6 RIU are achieved. The 4th order WGM resonant spectrum can be picked out clearly by comparing with the simulation results, and it shows a significant advantage against other modes in sensor sensitivity. In addition, the temperature dependent resonant wavelength shifts of different orders WGM are calculated. The 4th order WGM shows a lower response to temperature fluctuations comparing with other low radial modes. This may provide a solid theoretical and experimental foundaiton to build practical refractometric sensors with high sensitivity and low noise.