PUB - Publikationen an der Universität Bielefeld

Planar photonic waveguides enable ultrathin sample illumination in fluorescence microscopy over exceedingly large fields of view. Their fabrication has been based on hard coatings requiring sputter deposition and ion-beam lithography, making volume production cumbersome and thereby limiting their availability. Additionally, they are typically fabricated on top of opaque silicon wafers, which restricts the use to upright microscopes. Here, we present a low-cost photonic waveguide chip based on standard 170 μm thick glass coverslips coated with a micrometer-thin layer of EpoCore, a photoresist polymer with a high refractive index. These chips enable wide-field excitation for fluorescence microscopy and nanoscopy on inverted microscopes using fluorescence detection through the transparent substrate. Channel waveguides with varying widths provide uniform near-field illumination by evanescent waves for fields of view up to the millimeter scale. We demonstrate multicolor fluorescence excitation resulting in high-contrast immunofluorescence and super-resolution imaging with a resolution of approximately 60 nm.