Biological and chemical sensing with liquid droplet resonators

Fluorescence based sensing with liquid droplet resonators

We study optofluidic microlasers based on liquid droplet resonators for biological and chemical sensing. In our lab, we developed techniques to sensitively control the evaporation of droplets, manipulate them, and integrate them into optofluidic chips that contain microfluidic channels and optical fibers or waveguides. For increasing the sensitivity of a conventional fluorescence based sensor, we aim to benefit from dye lasing and FRET (Förster Resonance Energy Transfer) phenomena using droplet resonators. We also explore biolasing in droplet resonators for bio-sensing as well as for developing biologically controlled photonic devices.

Spectrum of a lasing fluorescently stained glycerol/water micrdodroplet suspended in a low refractive index oil.

Refractive index based sensing based on liquid droplet resonators

We have achieved performing ultrahigh resolution spectroscopy of liquid droplet resonators using tapered optical fibers. Due to the fragility of the experiments with fiber tapers we aim to extend our studies to alternative approaches employing different optical coupling geometries (e.g. free space coupling). Once the  experimental geometry for ultrahigh resolution spectroscopy of droplet resonators is established we will pursue high resolution sensing studies using techniques as cavity ringdown spectroscopy.