Analysis of gravitational effects on liquid lenses (ANGEL)

摘要

Liquid lenses have been developed as a means for fast and reliable variable-focus optics by using an adjustable curvaturein a liquid-liquid interface. The use of liquid lenses also provides the benefit of reducing the number of elements in asystem, and providing a degree of freedom without any moving parts. Different methods for surface curvature actuationhave been developed, including aperture adjustment, mechanical actuators, stimuli-responsive hydrogels, andmechanical-wetting. Current liquid lens designs are limited to small apertures (less than 4mm) and density-matchingfluids to lessen the negative effects of gravity. By creating a lens intended for use in a microgravity environment, theaperture size can be increased by orders of magnitude, and optimal fluids can be used regardless of their density. Using alarge-aperture (12mm) liquid lens, image and surface metrology was conducted using a fixed-focus configuration. TheSoftware Configurable Optical Test System (SCOTS) method was utilized to test the effect of microgravity, standardgravity, and hypergravity on the liquid lens during parabolic flights. Under standard gravity, the RMS wavefront error(WFE) was 27 wavelengths, while microgravity conditions allowed an improvement to 17 wavelengths RMS WFE. Testperformance can be improved by using lower viscosity fluids or longer duration microgravity flights. The experimentalso served as an engineering demonstration for the SCOTS method in an environment where other methods of opticalmetrology would be impossible.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.