Imprinted hydrogels for tunable hemispherical microlenses

• New development of printable ultraviolet curable hydrogel.
• Simple patterning process with an accurate control of the microlenses shape.
• Important focalisation variation of the imprinted hydrogel microlenses.

We report on the development of an ultraviolet curable hydrogel, based on combinations of poly(ethylene glycol) dimethacrylate (PEGMA), acrylic acid (AA) and N-Isopropylacrylamide (NIPPAm) for imprint lithography processes. The hydrogel was successfully imprinted to form dynamic microlens arrays. The response rate of the microlenses by volume change to water absorption was studied optically showing tunable focalisation of the light. Important optical refractive index change was measured between the dry and wet state of the microlenses. Our work suggests the use of this newly developed printable hydrogel for various imprinted components for sensing and imaging systems.

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