Attosecond pulse generation via multicolor beam superposition in the over-barrier ionization regime

• Published in: Journal of optics (2010) Vol. 20; no. 12; pp. 125403 - 125409
• Main Authors: Sarikhani, S, Farmani, A, Batebi, S
• Format: Journal Article
• Language: English
• Published: IOP Publishing 21.11.2018
• Subjects: attosecond; high order harmonic generation; hydrogen ion molecule
• ISSN: 2040-8978; 2040-8986
• DOI: 10.1088/2040-8986/aaef25

Based on coherent superposition of multicolor continuous wave beams, high order harmonics and attosecond pulse generation from a hydrogen molecular ion (HMI), H 2 + , with different internuclear distances, R, are studied. Driving pulse intensity was taken to be 400 TW cm−2, which can ionize an H 2 + ion with R > Rb = 2.4 a.u. over the barrier. It is seen that cutoff harmonic with respect to R decreases until the over barrier ionization threshold, Rb, then becomes almost uniform to the end of R = 10 a.u. whereas it is almost constant with respect to the spectral width of the beams, Δ . Besides attosecond pulse intensity increases versus R, and decreases with respect to Δ so that the most intense attosecond pulses can be generated from HMIs with R ≥ 5 a.u. via the pulses by Δ ≤ 0.03 a.u. Attosecond pulse durations were insensitive to both Δ and R.