Quantum ring: HHG spectrum control

Atoms, molecules , clusters and other systems driven by a strong laser field of frequency \omega_L can emit a spectrum of laserharmonics.The high harmonics generation (HHG) phenomen is strongly affected by the symmetries of the system. It is well known thatsystems with rotational symmetries emit only odd harmonics.Numerous researcher make mainly attention to the possibilities to set different initial conditions in order to control the spectrum.Recently, the study of nanotechnology is hot-topics and in particular the study of very symmetric systems such as fullerene,nanoring and structured nanoring (nanoring with identical and symmetric scattering centers).Therefore, it is natural and interestring to study the HHG emission from these systems and the effects of the symmetry break.In this poster we present the HHG spectrum emitted by a nanoring consisting of six symmetric scattering centers; as a second stepwe study the effects on the spectrum by small symmetry breakings. We show that tiny modifications of th symmetry allow a goodcontrol of the spectrum.