Metal nanostructure lattices for laser applications.

Abstract

processing to smart phone integration for augmented reality. Control over the shape and electromagnetic properties of the beam is desirable for these applications as well as new technologies. While the applications of lasers have exploded, nanofabrication technologies have also advanced at a rapid pace. This has allowed for the integration of lasers with complex nanostructured surface, known as metasurfaces, to control the wavefront and polarisation of the beams. One type of metasurface is a lattice of subwavelength plasmonic nanostructures with periods comparable to the wavelength of light. These lattices host high quality factor resonances suitable for laser feedback and have the versatility to control many properties of the emitted beam, such as the polarisation and direction. The focus of this work is to design and characterise new lattices resonances for laser applications. At the same time, the required fabrication techniques and an understanding how imperfections impact these resonances is developed.

Lattice resonances with a single element unit cell are studied and compared against dual element lattices using fabrication, modelling and optical characterisation techniques. Dual element lattices are fabricated with structure diameter differences as small as 10 nm and the effect of disorder on these lattices is investigated. These lattices are refined and resonances with elliptical polarisation are discovered and analysed. These unique lattice resonances and the effects of disorder presented in this work provide a foundation for building on-chip laser sources with complex polarisation properties.