Self-Sustaining Water Microdroplet Resonators Using 3D-Printed Microfluidics.

Microdroplet resonators provide an excellent tool for optical studies of water, but water microdroplets are difficult to maintain outside a carefully controlled environment. We present a method for maintaining a water microdroplet resonator on a 3D-printed hydrophobic surface in an ambient environment. The droplet is maintained through a passive microfluidic system that supplies water to the droplet through a vertical channel at a rate equivalent to its evaporation. In this manner, we are able to create and passively maintain water microdroplet resonators with quality factors as high as 3×108.

3D printed mounts for microdroplet resonators.

Liquid microdroplet resonators provide an excellent tool for optical studies due to their innate smoothness and high quality factors, but precise control over their geometries can be difficult. In contrast, three dimensional (3D) printed components are highly customizable but suffer from roughness and pixelation. We present 3D printed structures which leverage the versatility of 3D printing with the smoothness of microdroplets. Our devices enable the reliable creation of microdroplet resonators of varying shapes and sizes in an ambient environment, and our coupling scheme allows for high control over droplet position.