Using rigorous and realistic numerical simulations, staff in the Nanophotonics and Theory and Modeling groups have recently demonstrated that a single semiconductor nanocrystal, or quantum dot, can cancel the scattering and absorption by a much larger metal nanostructure. Placing a quantum dot near a metal is known to strongly modify the rate at which the dot emits light. If the interaction between the dot and the metal is strong enough, scattering and absorption by the metal can be nearly eliminated at the quantum-dot resonance frequency, according to the simulations. This occurs even though the dot by itself simply absorbs light, and even though this absorption is nearly 100,000 times smaller than absorption by the metal nanostructure.

A quantum-dot/metal nanoparticle hybrid structure that could be fabricated lithographically.

Scattering spectra for the structure when the corners of the metal nanoparticles have a curvature of 5 nm (solid squares) and 2 nm (open squares), calculated using the FDTD method. The lines are fits to a coupled-oscillator model.

X. Wu, S. Gray, and M. Pelton, “Quantum-dot-induced transparency in a nanoscale plasmonic resonator,” Opt. Express.,18, 23633-23645 (2010).

The Center for Nanoscale Materials is an Office of Science User Facility operated for
the U.S.Department of Energy Office of Science by Argonne National Laboratory