Resonance enhancement of harmonics in laser-produced Zn II and Zn III containing plasmas using tunable mid-infrared pulses

Abstract

We demonstrate the generation of enhanced tuneable harmonics of the mid-infrared (1250−1400 nm), 65 fs pulses in laser-produced zinc plasma in the regions of Zn II and Z III autoionizing states (77 and 68 nm, respectively). The role of singly and doubly ionized zinc in the modification of harmonic spectra was analyzed by variation of plasma formation conditions. Microprocesses and the propagation effect are also discussed to describe the narrowing of enhanced emission spectra.

Spectral caustic in two-color high-order harmonic generation: Role of Coulomb effects

“…Under the used approximations the phase-matching integral leads to the phase-matching factor which is formally the same as in the stationary case, but the factor itself depends on ξ. Thus, one can use the Gabor transform S(ω, ξ) of the microscopic response µ(ξ) and write the macroscopic response after propagation as: 21) where N is the atomic density and z f ull is the target thickness.…”

Application of 150 kHz Laser for High-Order Harmonic Generation in Different Plasmas

“…The observed HHG spectra under these conditions have shown the resonance-induced amplification at different wavelengths, corresponding to different transitions. In particular, the use of a near-infrared laser and its second harmonic (1300 nm + 650 nm [8]) for pumping Zn plasma led to the generation of amplified H15 (86.7 nm), which was due to the influence of some strong Zn II transitions, particularly the 3d 10 4s-3d 9 4s4p transition [31]. Our studies suggest that this ionic transition can be responsible for the enhancement of H11 while using the 1030 nm laser.…”

“…The most frequently used technique for the formation of the sources of coherent XUV radiation is the high-order harmonic generation (HHG) in gases. HHG at different pulse repetition rates was reported in the case of gas media [7][8][9][10][11]. However, the main drawback of HHG is the low conversion efficiency.…”

Method of XUV attosecond pulse characterization using two-photon resonant Raman-type transition

“…Moreover, for transitions in atomic gases Δq is a rather high number (typically from 4 to 10), so a relatively small tuning of ω 0 allows satisfying the condition. Note that a much wider tuning of the fundamental frequency is achieved using mid-IR OPA laser systems for HHG in gases [26][27][28][29] and plasma plumes [30][31][32][33].…”