Applications of the liquid core optical ring resonator platform

Abstract

ABSTRACT The liquid core optical ring resonator (LCORR) integrates an array of optical ring resonators into a microfluidics channel. The LCORR is made of a micro-sized glass capillary; the circular cross-section of the capillary acts as an optical ring resonator while the resonating light interacts with the fluid sample passing through the core. Q-factors larger than 10 7 have been achieved in LCORRs on the order of 100 micrometers in diameter. This implies an effective interaction length between the evanes cent field of the resonator and the fluidic core of over 10 cm. The novel integrated architecture and excellent photonic performance lead to a number of applications in sensing, analytical chemistry, and photonics. For the last decade, optical ring resonators have been explored for label-free bio/chemical detection. The LCORR architecture possesses the same capabilities as other optical ring resonator bio/chemical sensors while also integrating micro-capillary-based fluidics with the sensor head. The integrated fluidics design in combination with the micro-sized sensor head and pico-liter sample volume lead to a lab-on-a-chip sensor for biomolecules, such as biomarkers and specific DNA sequences. Also, because the ring resonator creates a high-intensity field inside the microfluidic channel, the LCORR is an excellent micr ofluidic platform for surface-enhanced Raman scattering (SERS) detection in silver colloids. Fina lly, the high quality factor of the capillary-based resonator enables novel opto-fluidic devices, such as dye lasers. We will discuss the details of these concepts and present our research results in each of these applications. Keywords: Ring resonator, whispering gallery modes, label-free detection, microfluidic laser, SERS.