Optical micro- and nanoresonators for biochemical sensing

Abstract

Biochemical sensors are indispensable to the biochemical detection system. According to their sensing principles, biochemical sensors can be divided into electronic sensors, optical sensors, thermal sensors, and so on, among which optical sensors have the unique advantages of fast response, high sensitivity, low detection limit, and immunity to electromagnetic disturbances. In recent years, optical biochemical sensors have been intensively investigated for their potential applications in biomedical diagnosis and environmental monitoring. Some of them have already been commercialized, such as enzyme-linked immunosorbent assay (ELISA), surface plasmon resonance (SPR) sensors, and optical fiber sensors. In the meantime, more and more novel optical biochemical sensors are emerging at a fast pace. There is especially a great deal of interest in biochemical sensors based on optical micro-/nanoresonators, due to their advantages of small size, small sample consumption, real time detection, fast response, high sensitivity, and low detection limit. Optical micro-/nanoresonators have micro-/nanoscale dimensions, which can confine light in small volumes, and have high Q/V ratios (i.e., Q-factor/mode volume ratio). In optical micro-/nanoresonator-based sensors, the light-analyte interaction is enhanced so that high sensitivity and low detection limit can be achieved. In this chapter, we focus on the optical micro-/nanoresonator-based biochemical sensors. We will discuss three kinds of optical micro-/nanoresonators, that is, Fabry–Perot microresonators, photonic crystal nanoresonators, and whispering gallery mode microresonators, and their applications in biochemical detection.