Nanoscale constriction as a source of plasmons for plasmonic nanocircuitries

We investigate spontaneous light emission by electrons passing through a nanoscale metal constriction and find that the Purcell-enhanced emission is engendered by two distinct mechanisms. In the first mechanism emission is caused by electron colliding with the effective potential of the mesoscopic contact while the second mechanism involves collisions of electrons with the walls of the constriction. We find that multiple collisions with the walls can lead to the orders-of-magnitude higher light emission probability in comparison to a single collision with the effective potential.