Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, via Campi Flegrei, 34—Comprensorio A. Olivetti, 80078 Pozzuoli, Naples, Italy.
Opt Lett. 2013 Jun 1;38(11):1951-3. doi: 10.1364/OL.38.001951.
We report on a method for surface plasmon resonance (SPR) refractive index sensing based on direct time-domain measurements. An optical resonator is built around an SPR sensor, and its photon lifetime is measured as a function of loss induced by refractive index variations. The method does not rely on any spectroscopic analysis or direct intensity measurement. Time-domain measurements are practically immune to light intensity fluctuations and thus lead to high resolution. A proof of concept experiment is carried out in which a sensor response to liquid samples of different refractive indices is measured. A refractive index resolution of the current system, extrapolated from the reproducibility of cavity-decay time determinations over 133 s, is found to be about 10(-5) RIU. The possibility of long-term averaging suggests that measurements with a resolution better than 10(-7) RIU/√Hz are within reach.
我们报告了一种基于直接时域测量的表面等离子体共振（SPR）折射率传感方法。在 SPR 传感器周围构建了一个光学谐振器，并测量其光子寿命作为折射率变化引起的损耗的函数。该方法不依赖于任何光谱分析或直接强度测量。时域测量实际上不受光强波动的影响，因此具有高分辨率。进行了一项概念验证实验，其中测量了传感器对不同折射率的液体样品的响应。从在 133 秒内确定腔衰减时间的重复性推断，当前系统的折射率分辨率约为 10(-5) RIU。长期平均的可能性表明，分辨率优于 10(-7) RIU/√Hz 的测量是可行的。
