Optogenetics is a fast growing neuromodulation technique which can remotely manipulate the specific activities of targeted neurons with irradiation of light. It benefits exploration of neuron network dynamics and also clinical studies such as retinal prosthesis. Light emitting diode (LED) offers a great option as the light source for optogenetics because it is small, reliable and easy to control. Especially, arrays of LEDs have been developed to enable multisite stimulation. A major drawback of LED is its intrinsically low out-coupling efficiency of light as a result of a large emitting angle around 90° to 120°. In this thesis, the employment of μ-lens array has been proposed to couple with LED and target the improvement of light out-coupling efficiency, which will lead to a higher spatial resolution for optical neural stimulation. A number of techniques, including surface tension modification, soft lithography, thermal reflow, and self-organized dewetting, have been studied to fabricate the array of μ-lenses on a flexible polymer substrate. Surface morphology of such μ-lens array has been analyzed both experimentally and theoretically. Experiment in the medium of gelatin has been carried out to mimic the light irradiation property in the natural tissue.
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