Nanoscale Transfer Printing for the Heterogeneous Integration of Semiconductor Nanowire Lasers

Nanowire lasers have revolutionized photonics providing highly localised coherent light sources at the nanoscale. Nevertheless, given the ultra-small dimensions of nanowire lasers, their accurate integration at targeted positions on selected substrates and pre-designed nanophotonic platforms remains a fundamental technological challenge. Here we present a new nanoscale transfer printing (nano-TP) technique overcoming this critical issue, and permitting the highly precise integration of individually-selected semiconductor nanowires from different materials (e.g. InP, GaAs) onto a diversity of substrates (e.g. polymer, silicon, silica, metals) and pre-fabricated optoelectronic systems. We will show that this hybrid nanofabrication technique yields very high placement accuracy
$(< 1\mu \mathrm{m})$
as well as full orientation angle control for the integrated nanowire lasers. Nano-TP therefore allows the development of tailored nanophotonic modules using semiconductor nanowire lasers as building blocks. During the talk, I will introduce our recent results demonstrating the fabrication of complex, user-defined spatial arrangements, e.g. 1-/2-Dimensional micrometric arrays with different types of nanowire lasers. We will also present our work on the integration of nanowire lasers onto pre-patterned on-chip waveguide systems (built on both planar and mechanically flexible substrates). Finally, we will review our ongoing activities towards bespoke hybrid nanowire laser systems enabled by nano-TP fabrication processes.