Light as fuel

Abstract

Research in nanophotonics is opening conceptually new paths to address the grand challenge of using light to generate chem. fuels. This is the challenge of direct synthesis of energy-dense chem. fuels from solar energy, including hydrogen from water splitting and reduced products of carbon dioxide. I will discuss recent advances in nanophotonics to enable advances in efficiency and selectivity for photocatalysis and light-driven photoelectrocatalysis. Another grand challenge for nanophotonics is the use of light as a rocket fuel. This is the challenge of designing light-propelled spacecraft capable of reaching the stars beyond our solar system, since light itself is the only fuel capable of propelling spacecraft to the relativistic speeds needed to achieve interstellar travel. Recently, the Breakthough Starshot initiative has captured scientific imagination and motivated thinking about conceptual prototypes for light-driven spacecraft that could reach nearby stars within a human lifetime. I will describe how this audacious concept may be closer than we imagine, if advances in materials and nanophotonics can enable key concepts for spacecraft propulsion, instrumentation and communications.