We develop a highly efficient approach for the modulation of photonic signals at the nanoscale, combining an ultrasubwavelength plasmonic guiding scheme with a robust electroabsorption effect in degenerate semiconductors. We numerically demonstrate an active electro-optical field-effect nanoplasmonic modulator with a revolutionary size of just $25\times 30\times 100{\mathrm{nm}}^3$, providing signal extinction ratios as high as 2 at switching voltages of only 1 V. The design is compatible with complementary metal-oxide-semiconductor (CMOS) technology and allows low-loss insertion in standard plasmonic and Si-photonic circuitry.

• Received 9 November 2011

DOI:https://doi.org/10.1103/PhysRevLett.109.053901