E-field control of the optical properties of liquid micro-optical elements

Micro-optical elements and related technologies are becoming increasingly important in a number of areas. There are many different methods of fabricating these micro-optical elements. One such technique to produce microlenses is the UV-curable resin method. This method involves the application of droplets of UV-curable resin to a substrate, which can then be cured using UV light. The quality of the lenses produced using this method can vary due to a number of experimental difficulties. These include the fact that the UV resin shrinks as it is cured. This shrinkage effect is a difficult problem, as it is a property of the UV material and the substrate. The ability to pre-shape the liquid droplet may enable the manufacturer to compensate for this shrinkage. In this paper we propose a method to generate a controlled perturbation of the liquid profile and hence the optical properties of the final lens. We describe our method of inducing variations in the droplet profile using an applied electric field. This method enables the fabrication of aspheric lenses. The analysis of this fabrication method requires the development of an accurate lens profile measurement system. A number of techniques can be used to examine the resulting lens elements including mechanical techniques such as Dektak profilometry and optical techniques such as interferometric techniques including laser profiler and white light profiler. In this paper we give the details of the modified Mach-Zehnder interferometric measurement system used, discuss the optical properties of the lens and show a demonstration of the perturbation of the lens profile.