Adiabatic nanofocusing of channel plasmon polaritons.

Using the analytical description of channel plasmon polaritons (CPPs) developed recently [Opt. Lett.34, 2039 (2009)], we consider the adiabatic CPP nanofocusing in V grooves with linearly decreasing groove angles, deriving closed-form expressions for local field enhancements. Calculations at telecom wavelengths predict the possibility of reaching the intensity enhancements exceeding approximately 1200 for realistic groove tapers cut into gold. Our conclusions are in good agreement with the results of previous investigations.