Abnormal pulse duration dependence of the ionization probability of Na atoms in intense laser fields
نویسندگان
چکیده
We studied the ionization probability of Na atoms in an intense Ti–sapphire laser at 800 nm versus the laser pulse duration. The ionization probabilities for the Na(3s) and Na(3p) states were found to vary non-monotonically with the pulse duration at a constant peak laser intensity. The abnormal (non-monotonic) pulse duration dependence was traced to the competition between resonant and non-resonant multiphoton ionization processes, which occurs when the frequency broadening due to the finite pulse duration is compatible with the energy difference between the excitation energy and multiphoton energy.
منابع مشابه
Effects of intense laser pulse properties on wake field acceleration in magnetized plasma: Half-Sine Shape (HSS) and Gaussian Shape (GS) pulses
In this paper, we have simulated the excitation of wake fields in the interaction of an intensive laser pulses having Half-Sine and Gaussian time envelopes with a fully ionized cold plasma using particle in cell (PIC) method. We investigated the dependency of wake filed amplitude to different laser and plasma parameters such as laser wavelength, pulse duration and electron number density. In ad...
متن کاملTheory of Gas Ionization by Intense Electromagnetic Fields
The distribution function of the electrons produced in the interaction between an intense electromagnetic wave and a neutral gas is derived and is shown to be nonequilibrium and anisotropic. By assuming that the time scale of gas ionization is much greater than the field period, it is shown that the electron distribution function formed in microwave and optical discharges has sharp anisotropy a...
متن کاملNumerical Simulation of an Intense Isolated Attosecond Pulse by a Chirped Two-Color Laser Field
We investigate theoretically the high-order harmonic spectrum extension and numerical generation of an intense isolated attosecond pulse from He+ ion irradiated by a two-color laser field. Our simulation results show that the chirp of the fundamental field can control HHG cutoff position. Also, these results show that the envelope forms of two fields are important factors for controlling the re...
متن کاملMultiphoton Ionization of Atoms by an Ultrashort Laser Pulse
Closed analytical expressions for the probability of multiphoton ionization of atoms and ions by a time-varying electric field %(t) are obtained by the imaginary time method. These expressions apply for arbitrary values of the Keldysh parameter γ. The dependence of the ionization probability and the photoelectron momentum spectrum on the shape of an ultrashort laser pulse is considered. © 2001 ...
متن کاملPhotoelectron spectra and high Rydberg states of lithium generated by intense lasers in the over-the-barrier ionization regime
We calculated photoelectron energy and momentum spectra and the population of high Rydberg states of lithium atoms by intense 785 nm laser pulses at intensities in the over-the-barrier ionization (OBI) regime. The calculated spectra are compared to experiments reported in Schuricke et al. [Phys. Rev. A 83, 023413 (2011)]. It is shown that in the OBI regime, due to strong depletion of the ground...
متن کامل