Noise-Induced Limits of Detection in Frequency Locked Optical Microcavities
Noise-Induced Limits of Detection in Frequency Locked Optical Microcavities
复制标题
DOI：
10.1109/jlt.2020.3010869
复制
发表时间：
2020-11-15
影响因子：
4.7
通讯作者：
Su, Judith
中科院分区：
文献类型：
--
作者：
Hao, Shuang;Su, Judith
超高质量（Q）回音壁模式（WGM）光学微腔因其长的光子限制时间而被证明是敏感的生物分子传感器。我们以前已经实验证明，被称为FLOWER（锁频光学回音倏逝谐振器）的系统可以检测单个大分子。FLOWER使用频率锁定结合平衡检测和数据处理，大大提高了超高Q微腔的灵敏度，稳定性，信噪比（SNR）和检测限。在这里，我们提出了分析基础的花，并通过数值模拟探索其检测极限。我们研究的关键参数，如Q因子和频率调制深度的FLOWER的SNR的影响。我们证明了锁频光学微腔系统不仅受到激光强度噪声的限制，而且还受到来自接收器的散粒噪声的限制。使用中值滤波结合阶跃拟合算法，频率锁定的超高Q微腔可以检测到谐振位移小至0.05 attometers在一毫秒的时间间隔。我们的研究结果可以指导实验参数的选择，以实现更好的传感性能，在各种目标的应用，包括蛋白质-蛋白质相互作用的基础研究和医学诊断和生物学。
Ultra-high quality (Q) whispering gallery mode (WGM) optical microcavities have been shown to be sensitive biomolecular sensors due to their long photon confinement times. We have previously experimentally demonstrated that a system known as FLOWER (frequency locked optical whispering evanescent resonator) can detect single macromolecules. FLOWER uses frequency locking in combination with balanced detection and data processing to greatly improve the sensitivity, stabilization, signal-to-noise ratio (SNR), and the detection limit of ultra-high-Q microcavities. Here we present the analytical basis for FLOWER and explore its limits of detection via numerical simulation. We examine the effects of key parameters such as Q-factor and frequency modulation depth on the SNR of FLOWER. We demonstrate that the frequency locked optical microcavity system is limited by the shot noise from the receiver, as well as the laser intensity noise. Using median filtering in combination with step-fitting algorithms, frequency locked ultra-high-Q microcavities can detect resonance shifts as small as 0.05 attometers at one millisecond time intervals. Our results can guide the choice of experimental parameters to achieve better sensing performance in a variety of target applications, including fundamental studies of protein-protein interactions and medical diagnostics and prognostics.