Versatile Direct Laser Writing Lithography Technique for Surface Enhanced Infrared Spectroscopy Sensors

A challenge for design, testing, and fabrication of nanostructured chemical sensors is the fabrication of mm² size arrays of nanostructures in a reasonable time. Herein, we introduce and show how direct laser writing (DLW) in positive-tone photoresists, followed by lift-off process, can be used for fast fabrication (up to three times faster than a comparable electron beam lithography system) of arrays of nanoscale plasmonic structures with a great level of control over the design and dimensions of the nanostructures. We demonstrate the function of nanostructured arrays, fabricated by various DLW approaches, with surface enhanced infrared absorption (SEIRA) detection of nine vibrational modes of PMMA. We also discuss the tunability of the plasmonic resonance - and hence the spectral detection range - by alteration of the size and array parameters of the nanostructures, and demonstrate the flexibility of this fabrication method by showing devices made of various substrate and antenna materials.