Optomechanical limits of tubular optofluidics

• Applicant: Professor Dr. Hans Zappe
• Subject Area: Microsystems
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 411766042

The objective of the current project is to research the optical performance limits of all-liquid optofluidic imaging systems. The primary optical performance considerations are aberration control and actuation speed. At the conclusion of the project, we intend to demonstrate aberration-corrected fluidic imaging systems which can be actuated at speeds which make them competitive with classical, bulk opto-mechanical components.The tubular optofluidic technology is based on controlled manipulation of numerous liquids, with precisely defined refractive indices, densities and immiscibility, packaged in a completely fluid-filled cylindrical tube. Actuation of the phase fronts (menisci) is through electrowetting, controlled by applied voltages on a structured foil on the inside surface of the tube.Key to enhanced aberration control and a more precise manipulation of the liquid phase fronts for high-spatial-frequency wavefront modulation is realization of a high electrode density inside this fluidic tube. Detailed analysis of the hydrostatics of the system will be undertaken, as will a detailed design of the liquid/liquid and liquid/surface interfaces. Through realization of 64 azimuthally-distributed electrodes, the limits to high-spatial-frequency definition of the phase fronts will be determined.In addition, high-speed actuation of fluidic imaging and scanning systems will require new and novel liquid and dielectric interface materials, to optimize voltage and electric field distributions and reduce actuation time constants. Through hydrostatic and hydrodynamic analysis of the all-liquid imaging systems, it is expected that actuation speeds suitable for a wide variety of applications will result.As demonstrators for high-performance all-liquid imaging and scanning systems, a tunable anamorphic imager; a 360-degree optical scanner with no mechanically-moving parts; and an aberration-corrected tunable lens system will be realized.We expect that these results will make sufficient scientific and technological impact so that optofluidic components and systems will become significantly closer to usability in real-world applications.

• DFG Programme: Research Grants