Towards fabrication of optomechanical actuators by two-photon polymerisation

Abstract

This thesis describes theoretical and experimental progress toward making optical actuators: structures with nanoscale features that change shape when illuminated by light. Experiments on making nanoscale structures were conducted using the Nanoscribe: a commercial two-photon polymerisation machine. The Nanoscribe produces solid structures in a liquid resist called IP-L 780 in regions of the order of 100 nm around the focus of a laser beam, which is moved relative to the resist to make extended structures. These experiments tested the feature size of structures made using the Nanoscribe, and the optical and mechanical properties of the polymer it produces. Structures were created to test the effects on feature size of changing the power of the laser beam and the speed of its motion through the resist. Models were created to explain the width and depth of parts of features. These models did not match the experimental data, but the information on feature size is useful for designing structures. Making optical actuators requires information about mechanical properties of the polymer. Beams supported by a block at each end were created to test the mechanical properties of the solidied IP-L 780. These structures were designed to bend when exposed to forces to yield information about their Youngs modulus. Those forces were applied using a profiler. The results could not be explained by the models used to design the structures but directions for further research into the mechanical properties are considered. A series of Bragg stacks were made using the Nanoscribe to test the optical properties of the polymer and find out whether it could be used reliably to make structures with complex internal structure required to produce optical effects such as interference. The results were compatible with some of the stacks having the complex internal structure required.

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Identifiers

ORCID for Timothy Freegarde: orcid.org/0000-0002-0680-1330

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