Enhanced XUV harmonics generation from diatomic gases using two orthogonally polarized laser fields

Ganjaboy S Boltaev,Ganjaboy S Boltaev,Vyacheslav V Kim,Mazhar Iqbal,Ali S Alnaser,Rashid A Ganeev,Rashid A Ganeev,Naveed A Abbasi

doi:10.1038/s41598-021-85114-8

Abstract

Enhanced high repetition rate coherent extreme ultraviolet (XUV) harmonics represent efficient probe of electron dynamics in atoms, molecules and solids. In this work, we used orthogonally-polarized two-color laser field to generate strong even and odd high order harmonics from molecular gas targets. The dynamics of odd and even harmonics from O2, and N2 gases were investigated by employing single- and two-color laser fields using the fundamental radiation and second harmonic of 1030 nm, 37 fs, 50 kHz pulses. The relative efficiencies of harmonics were analyzed as a function of the thickness of the barium borate crystal used for second harmonic generation. Defocusing-assisted phase matching conditions were achieved in N2 gas for different groups of XUV harmonics.

Highlights

Enhanced high repetition rate coherent extreme ultraviolet (XUV) harmonics represent efficient probe of electron dynamics in atoms, molecules and solids
The different intensity ratios ( Iω/I2ω ~ 40, 20, 10) between two-color laser fields generated in 0.1 mm, 0.4 mm, and 1.5 mm thick-barium borate (BBO) crystals led to the enhancement of XUV harmonics in different ranges of high-order harmonic generation (HHG) with photon energies from 15 to 50 eV; and showed dependence of cutoff energy of XUV harmonics generated in diatomic gases on the thicknesses of the nonlinear crystals (Fig. 5b)
We have demonstrated the enhancement of XUV harmonics intensity generated in diatomic gases using orthogonally-polarized two-color laser pulses

Summary

Introduction

Enhanced high repetition rate coherent extreme ultraviolet (XUV) harmonics represent efficient probe of electron dynamics in atoms, molecules and solids. The pursuit for table top intense coherent sources in different ranges of extreme ultraviolet (XUV) drives the continuous investigations of high-order harmonic generation (HHG) during the interactions of ultrashort infrared femtosecond pulses with atoms, molecules, laser plasma, and solid targets[1,2,3,4,5,6]. The generation of bright harmonics in the range above 20 eV using two-color field was reported in19, where formation of highly-efficient source of femtosecond XUV pulses at 50 kHz repetition rate was implemented under tightly focusing of ultraviolet SH (2 ω ; at the wavelength of λ = 390 nm) into Kr gas jet. The application of two-color field to cover this spectral range with strong harmonics can be utilized in analyzing the dynamics of electrons in various quantum materials[21]

Methods

Results

Discussion

Conclusion