Real-time detection and analysis of Whispering gallery mode resonance in high-throughput flowing monodisperse microdroplets

•We show a light coupling with highly monodisperse liquid microdroplets.•Microdroplets are produced and manipulated at kHz rates thanks to a microfluidic device.•We detect and analyze Whispering gallery mode resonances (WGMs) which are versus wavelength and time.•We investigate a new route for high-throughput label-free biosensing using droplet-based microfluidics technology.

We investigate light coupling into highly monodisperse liquid microdroplets, which are produced and manipulated at kHz rates in a microfluidic device. We show that such coupling leads to Whispering gallery mode resonances (WGMs) which are detected and analyzed versus time during the fast displacement of microdroplets into the microfluidic channel. Our results show that droplet-based microfluidics may be applied advantageously in the promising field of high-throughput label-free biosensing.