Azeem Farhan, Chaudhry Muhammad Rehan, Anwar Muhammad Sohail, Khan Haseeb Ahmad, Ma Li, Khan Adnan Daud
The Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin, New Zealand.
Department of Physics, University of Otago, Dunedin, New Zealand.
J R Soc N Z. 2024 Aug 29;55(6):1732-1756. doi: 10.1080/03036758.2024.2395909. eCollection 2025.
In this work, we discuss and experimentally investigate the whispering gallery modes (WGMs) in a 500 μm radius silicon sphere. We begin by reviewing the basics of WGM resonators, followed by simulations and experimental results obtained with the aforementioned silicon spherical WGM resonator. The recorded WGM signatures in the transmission and scattering spectra excited, in the near-infrared (near-IR) region, agree well with the simulations. Thermo-optic tuning of these WGMs is achieved by introducing a pump laser in the violet-blue region. Red-shifts in wavelength are observed, which increase with the increase in the pump power. A shift of 0.63 nm is observed at a pump power of 6.32 mW. We also study switching by analysing the transient response of the WGM spectra. The measured WGMs exhibit high quality factors ( ), which along with the aforesaid tunability, demonstrates the potential of spherical silicon resonator as a platform for photonic applications, e.g. sensing and communication. In summary, this work contributes towards the understanding of the fundamental physics of WGMs and provides insights into silicon WGM resonators.
在这项工作中，我们讨论并通过实验研究了半径为500μm的硅球中的回音壁模式（WGMs）。我们首先回顾了WGM谐振器的基础知识，随后给出了使用上述硅球WGM谐振器获得的模拟结果和实验结果。在近红外（near-IR）区域激发的传输和散射光谱中记录的WGM特征与模拟结果吻合良好。通过在紫蓝光区域引入泵浦激光实现了这些WGM的热光调谐。观察到波长红移，其随泵浦功率的增加而增大。在泵浦功率为6.32mW时观察到0.63nm的波长偏移。我们还通过分析WGM光谱的瞬态响应来研究开关特性。测量得到的WGM具有高品质因数（ ），连同上述可调谐性，证明了球形硅谐振器作为光子应用平台（如传感和通信）的潜力。总之，这项工作有助于理解WGM的基本物理原理，并为硅WGM谐振器提供了见解。
