Abstract
Surface plasmon resonance enhanced high harmonic generation of intense short pulse lasers in xenon clusters is investigated. A laser prepulse partially ionizes the cluster atoms, turning them into plasma balls. As the main pulse arrives, plasma electrons execute large amplitude oscillations, creating a space charge field much higher than the laser field at surface plasmon resonance. The bound electrons under this field move out of the ions and return back with large residual energy. On recombination, they produce high harmonics. The number of photons emitted by the xenon clusters per second per frequency interval decreases with the emitted photon frequency.
Highlights
High harmonic generation (HHG) of an infrared laser is a subject of continued interest due to its potential applications, e.g., X-ray generation, production of attosecond pulses, molecular tomography, etc
For off-axis clusters, the tunneling probability of electrons from the ions strongly decreases with radial distance as the laser field of the Gaussian beam falls off; the region of high harmonic generation is severely restricted to the vicinity of the laser axis, within a fraction of laser spot size
III, we study the probability of emission of photons on recombination of electrons with parent ions and calculate the total number of photons emitted by the cluster per second per unit frequency interval when illuminated by the laser beam
Summary
High harmonic generation (HHG) of an infrared laser is a subject of continued interest due to its potential applications, e.g., X-ray generation, production of attosecond pulses, molecular tomography, etc. The HHG is understood as follows. A linearly polarized sub-picosecond laser pulse of ∼1013 to 1016 W/cm intensity is impinged on a gaseous target. Gases embedded with clusters offer an efficient nonlinear medium for high harmonic generation using attosecond laser pulses. This space charge field acquires a much larger value than the laser field and induces the bound electrons of cluster ions to tunnel out. The electrons move in the oscillatory space charge field and return back to the original ions with enhanced energy, producing high frequency photons on recombination. For off-axis clusters, the tunneling probability of electrons from the ions strongly decreases with radial distance as the laser field of the Gaussian beam falls off; the region of high harmonic generation is severely restricted to the vicinity of the laser axis, within a fraction of laser spot size.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
