Current-Based High-Sensitivity Differential Detection of Light Power Using Si Photodiodes in Bridge Configuration for Chemical/Biological Optical Sensing
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- 作者：Andrea De Marcellis ; andrea.demarcellis@univaq.it ; Elia Palange
- 关键词：Current-Based Approach ; High Sensitivity System ; Differential Measurement ; Silicon Photodiode ; Bridge Configuration ; Optical Sensing ; Chemical and Biological Detection.
- 刊名：Procedia Engineering
- 出版年：2016
- 出版时间：2016
- 年：2016
- 卷：168
- 期：Complete
- 页码：1300-1303
- 全文大小：139 K
- 卷排序：168
文摘
We present a new optoelectronic technique based on the differential measurement of currents for the detection of the variations of low concentrations of chemical and biological substances by measuring light power absorption through two Si-photodiodes (SiPD) in a bridge configuration. The solution exhibits high sensitivity, linear response and allows the compensation of the initial bridge unbalance without changing its elements so optimising signal amplification gain and detection resolution. The technique shows unique performances with respect to voltage amplitude measurements performed by lock-in amplifiers. Moreover, the experimental apparatus is simple and suitable for portable integrated sensor systems. Its main performances have been evaluated through a prototype PCB demonstrating the capability to detect light power variations with a settable maximum sensitivity of 30mV/nW and a resolution of 33pW.