Plasmon nanofocusing for nano-sensing and nano-optical switching (Invited Paper)

Controlling the physical and electronic properties of materials through optics holds significant appeal for both foundational scientific exploration and the advancement of optoelectronic technologies. A natural progression involves scaling down devices to the nanoscale, necessitating a reduction in the volume of optical interactions to the nanoscale. Optical antennas, though capable of confining light, fall short due to the requirement of illuminating them with a diffraction-limited focal spot, resulting in unintentional illumination of the sample over a larger volume. In contrast, plasmon nanofocusing physically separates the illumination and the nano-light generation sites, enabling background-free and truly confined nano-light. Furthermore, being a non-resonant phenomenon, plasmon nanofocusing is wavelength-independent, allowing for the generation of nano-light across a broad spectrum of wavelengths or even a white nano-light, suitable for nanoscale multi-sensing and optical switching applications. This talk will cover the generation of background-free, wavelength-independent nano-light and its potential applications in nanoscale sensing and optical switching.