Fluidic shaping and in-situ measurement of liquid lenses in microgravity.

In the absence of gravity, surface tension dominates over the behavior of liquids. While this often poses a challenge in adapting Earth-based technologies to space, it can also provide an opportunity for novel technologies that utilize its advantages. In particular, surface tension drives a liquid body to a constant-mean-curvature shape with extremely smooth surfaces, properties which are highly beneficial for optical components.

Coupled instabilities drive quasiperiodic order-disorder transitions in Faraday waves.

We present an experimental study of quasiperiodic transitions between a highly ordered square-lattice pattern and a disordered, defect-riddled state, in a circular Faraday system. We show that the transition is driven initially by a long-wave amplitude modulation instability, which excites the oscillatory transition phase instability, leading to the formation of dislocations in the Faraday lattice. The appearance of dislocations dampens amplitude modulations, which prevents further defects from being created and allows the system to relax back to its ordered state.

Superradiant Droplet Emission from Parametrically Excited Cavities.

Superradiance occurs when a collection of atoms exhibits a cooperative, spontaneous emission of photons at a rate that exceeds that of its component parts. Here, we reveal a similar phenomenon in a hydrodynamic system consisting of a pair of vibrationally excited cavities, coupled through their common wave field, that spontaneously emit droplets via interfacial fracture. We show that the droplet emission rate of two coupled cavities is higher than the emission rate of two isolated cavities.

Intermediate States of Wetting on Hierarchical Superhydrophobic Surfaces.

Wetting transition on superhydrophobic surfaces is commonly described as an abrupt jump between two stable states-either from Cassie to Wenzel for nonhierarchical surfaces or from Cassie to nano-Cassie on hierarchical surfaces. We here experimentally study the electrowetting of hierarchical superhydrophobic surfaces composed of multiple length scales by imaging the light reflections from the gas-liquid interface. We present the existence of a continuous set of intermediate states of wetting through which the gas-liquid interface transitions under a continuously increasing external forcing.