Field enhancement on nano-structures inside dielectrics

The interaction between ultrafast laser pulses and the condensed matter has opened new frontiers in the physics and technology of light-matter interactions and laser micro-machining. The focusing of intense ultrafast laser pulses inside dielectric materials has led to the formation of nano-voids [1] and periodic nano-gratings. In the former case, the formation of dense plasma allows the excitation of electron plasma waves along the density gradient that can lead to the resonance absorption process. In the latter case, however, diffraction by the grating matches the incident laser energy into surface electromagnetic waves, known as surface plasmons, which propagate along the surface. In both cases, high energy absorption can be obtained. The electron plasma waves and surface plasmons are, therefore, unique properties in nano-structures for manipulating and confining the lasers.