Enhanced XUV harmonics generated in mixed noble gases using three-color laser fields

Area of Science:

• Atomic, Molecular, and Optical Physics
• Quantum Electronics
• Ultrafast Science

Background:

• High-repetition coherent extreme ultraviolet (XUV) harmonics are crucial for probing electron dynamics and fundamental physics.
• Previous studies utilized single-color laser fields for XUV harmonic generation.

Purpose of the Study:

• To demonstrate the generation of coherent XUV radiation using combined three-color (ω+2ω+3ω) laser fields in mixed noble gases.
• To investigate the influence of different noble gas ionization potentials on XUV harmonic generation.
• To compare XUV harmonic yields generated by three-color fields versus single-color fields.

Main Methods:

• Generation of a three-color laser field by combining fundamental, second-, and third-order harmonics of near-infrared pulses in nonlinear crystals.
• Use of mixed noble gases (He+Kr, He+Xe) as targets for XUV harmonic generation.
• Selection of gas targets based on ionization potentials to optimize harmonic cut-offs and intensities.

Main Results:

• Enhanced XUV harmonic intensities were observed in He+Kr mixtures using three-color fields compared to single-color fields.
• Suppression of XUV harmonic intensity was observed in He+Xe mixtures under three-color pumping due to high ionization potentials.
• Strong harmonic yields in the 25–80 eV photon energy range were achieved.

Conclusions:

• Combined three-color laser fields offer a viable method for enhancing coherent XUV harmonic generation in specific mixed noble gas systems.
• The choice of noble gas mixture and its ionization potential significantly impacts XUV harmonic yield and intensity.
• This technique provides a powerful tool for advanced studies in electron dynamics and fundamental physics.