Fabrication of asymmetric nanostructures for plasmonic force propulsion

The objective of this research is to manufacture and investigate the characteristics and use of asymmetric, metallic, nanostructures for plasmonic force propulsion, a developing method of nano-/picosatellite thrust generation. Visible to near-infrared light is focused onto sub-wavelength nanostructures to generate polarized oscillations of electrons on the surface of the metallic nanostructures (surface plasmon polaritons). The surface plasmon polaritons accelerate nanoparticle propellant away from the nanostructure, creating thrust. Previous numerical simulations have shown that asymmetric nanostructures can resonate strongly within the visible spectrum. This is the first experiment ever attempted and first to successfully demonstrate this resonance where the resonance peak is λ = 830 nm. The resonance peak of the experimental optical characterization agrees well with our computed model, showing an 11.2% difference. However, the off resonance behavior exhibits peak broadening where the variation of intensity with wavelength, off resonance, has an experimental slope that is 3.7 times less steep than the computed model. Furthermore, the optical transmittance of the sample is 2.1 times higher than computationally modeled. It is shown that the nanostructures are thermodynamically stable in the projected environmental conditions and have an equilibrium temperature of 746.4 K. Upon review of the experimental optical setup, we conclude that thrust generation is not possible with continuous irradiation of light and propose a method of synchronous dynamic acceleration of nanoparticle propellant by use of a pulsed light beam.