Nonlinear absorption of ultrashort ultrahigh intensity laser pulses in fullerene

Non linear absorption of intense few cycle laser pulses in fullerenes is studied by treating it as a laser driven nonlinear oscillator, using a rigid shell model. Efficient collisionless absorption of intense (Intensity I < 1018W/cm2) ultrashort laser pulses in fullerene (C60) is estimated owing to its extraordinary anharmonicty which is quite different than the conventionally used solid gas clusters. Compared to gas clusters nonlinear resonance in C60 has unusual characteristics. Factors other than nonlinear resonance which contribute in energy absorption in C60 are outlined. Strong dephasing of electrons with the laser field both at onset and during the dynamical oscillations leads to the efficient energy gain by the electrons. It is found that fullerene has a distinct threshold intensity requirement depending on its charge for efficient absorption. These properties make fullerene unique for efficient absorption of high intensity few cycle laser pulses.