Coherent Control of Ultrafast Nanoscale Localization of Optical Excitation Energy

We predict and theoretically investigate the unique possibility to control distribution of ultrafast local optical fields in nanosystems in space with nanometer resolution and in time on the femtosecond scale. While the spatial degrees of freedom of the optical radiation do not allow focusing of the light on nanoscale, the temporal degrees of freedom, i.e., phases of excitation femtosecond pulse, constitute efficient functional degrees of freedom that permit one to coherently control the distribution of the energy of local fields, concentrating it at a desired location at certain times. We study both a specially designed V-shape nanostructure and a random planar nanocomposite. Several types of exciting pulses are investigated, which has allowed us to distinguish effects of phase modulation and spectral composition of the excitation pulse. Possible applications of this effect include energy supply and control of ultrafast optical computations in nanostructures, local optical probing of nanosystems, including nanosensors of chemical and biological agents, and nanomodification of surfaces (nano-lithography).