Opto-fluidic ring resonator (OFRR) is a photonic technology originally invented in the PI's lab. The OFRR integrates the optical cavity of extremely high Q-factors (>107) with microfluidics, enabling efficient sample delivery and control of light through fluids. Because of these novel characteristics, the OFRR has broad applications in many fields, including bio/chemical sensors, photonic devices, and fundamental physics. In the proposed research, in particular, the PI wilo expand the OFRR study into fluorescence resonant energy transfer (FRET). FRET has been extensively employed in biological and chemical sensors. However, extremely low energy transfer efficiency beyond the Forster distance (2-10 nm) has severely deteriorated the FRET sensing capability, especially for large biomolecules. The PI's recent studies, along with those conducted earlier by other groups, have shown that FRET efficiency can be drastically enhanced by an optical cavity through long-range cavity assisted energy transfer and nonlinear lasing action. These properties can be exploited to overcome the limitations of the traditional FRET-based biosensing. The overall aim of the proposed research is to conduct a fundamental investigation into FRET processes in the OFRR and to harness the powerful OFRR and FRET technologiesto develop a novel miniaturized and highly sensitive photonic biosensing system that can be operated at even the single molecule level.
