Lab-on-a-chip bio/chemical sensing system based on the liquid core optical ring resonator

Abstract

The liquid core optical ring resonator (LCORR) sensor is a newly developed capillary-based ring resonator that integrates microfluidics with photonic sensing technology. The circular cross-section of the capillary forms a ring resonator that supports whispering gallery modes (WGM), which interact with the sample as it passes through the capillary. As in previous ring resonator sensor implementations, the interaction between the WGM evanescent field and the sample enables label-free detection. With a prototype of an LCORR sensor, we have achieved a refractive index detection limit of 10-6 RIU and a detection limit for protein of 2 pg/mm 2 . Several engineering developments have been accomplished as well, including a thermal noise characterization, a thermal stabilization implementation, integration of the LCORR with a planar waveguide array, and electro-kinetic sample delivery. In the near future, the LCORR will be integrated into a dense 2-dimensional sensing array by integrating multiple capillaries with a chip-based waveguide array. This lab-on-a-chip sensing system will have a number of applications, including environmental sensing for defense purposes, disease diagnostics for medical purposes, and as a lab tool for analytical chemistry and molecular analysis.