CMOS image sensor array for surface plasmon resonance spectroscopy

A novel surface plasmon resonance (SPR) sensor system using CMOS image sensor array is proposed in this paper. Recently, a simple SPR system was proposed by the author, which achieved high resolution and fast response time using a bi-cell photo-detector. However it requires mechanical adjustment process to balance two signals of the bi-cell before measurement. It requires not only additional time but also additional mechanical control unit, which is a source of the noise. It also suffers from the small linear range. The proposed method chooses a pixel as the center from many pixels, which gives the most balance of bi-cell signal. Therefore no mechanical adjustment is required. The method also overcomes the small linear range problem by switching the center adaptively during the test. Furthermore, it has several advantages of CMOS image sensor such as low cost, low power, and on-chip functionality, which makes the proposed SPR sensor system be a good candidate for field applications. A prototype CMOS image sensor chip with 12bits analog to digital converter is designed and fabricated with 0.5um AMI CMOS technology.