Laser-inscribed nanostructures and their applications in sensing, imaging and spectroscopy

Stable and large-scale optical nanostructures can be inscribed as surface relief in solid thin films of azobenzene materials. This occurs due to a unique photomechanical effect in which azobenzene molecules physically displace due to laser light, enabling the creation of distinct macro-scale patterns that mimic a laser interference pattern. This nanofabrication technique allows the creation of quasi-crystals and metasurfaces that, when coated with a metal layer, exhibit plasmonic properties in customizable narrow-band or wide-band wavelength regions. The resulting plasmonic nanostructures have been used by our group as biosensors for detecting proteins and bacteria, below the clinical threshold for disease detection, and they enabled the enhancement of Raman spectroscopy signals for the detection of toxins and contaminants in liquids. Furthermore, we developed novel imaging techniques that selectively enhance, filter and detect customizable wavelength bands using polarization-contrast imaging enabled by two-dimensional gratings