Spectral Tuning of Liquid Microdroplets

Liquid microdroplets standing on a superhydrophobic surface can also provide a three dimensional con¿nement for light. The use of superhydrophobic surfaces is very e¿cient and costless way to protect the sphericity and provide the position stabilization of liquid microdroplets. The whispering gallery modes (WGMs) of liquid microdroplets can have high quality factors due to the large contact angle. The liquid nature of the microdroplets provides large spectral tuning which can not be obtained by using solid microcavities. The large spectral tuning ofWGMs of liquid microdroplets can be obtained by the size change by using evaporation/condensation kinetics or the shape deformation by using electrowetting. In this thesis, ¿rst we demonstrate the large spectral tuning of a water-glycerol micro- droplet standing on a superhydrophobic surface by local heating experimentally by optical spectroscopy and computationally using a lumped system formulation of the mass and heat transfer between the microdroplet and the chamber. Second, we demonstrate reversible spectral tuning of the whispering gallery modes of glycerol-water microdroplets using electrowetting.