Overview of the optofluidic ring resonator: a versatile platform for label-free biological and chemical sensing.

Highly sensitive detection of biological and chemical analytes has significant importance within medical science, environmental monitoring, food quality, national security and defense. The opto-fluidic ring resonator (OFRR) is a relatively new solution for label-free optical sensing that is compatible with a versatile range of analytes. A capillary-based platform, the OFRR supports whispering gallery modes within its circular cross-section and conducts evanescent sensing within its hollow core. Herein, we provide an overview of the basic operation principles of the OFRR and some examples of its most important applications, including the detection of proteins, virus, DNA molecules, whole cells, vapors and pesticides.