Experimental Demonstration of Efficient Harmonic Generation via Surface Plasma Compression with Lasers

Area of Science:

• Plasma Physics
• Nonlinear Optics
• Laser-Matter Interactions

Background:

• High-order harmonic generation (HHG) efficiency is crucial for applications.
• Optimizing surface plasma scale length using high-contrast lasers is the conventional approach.
• Relativistic laser-solid interactions are sensitive to plasma conditions.

Purpose of the Study:

• To demonstrate a novel method for enhancing HHG efficiency.
• To achieve efficient harmonic generation without high-contrast lasers.
• To explore the use of radiation pressure for plasma compression.

Main Methods:

• Experimentally compressing large-scale surface plasma using a circularly polarized laser prepulse.
• Utilizing the radiation pressure of the prepulse to modify plasma scale length.
• Measuring harmonic generation efficiency under these conditions.

Main Results:

• Achieved efficient high-order harmonic generation by compressing surface plasma.
• Harmonic generation efficiency is comparable to methods using optimized plasma scale length with high-contrast lasers.
• The demonstrated scheme is robust and does not require high-contrast lasers.

Conclusions:

• Direct compression of surface plasma offers an alternative route to efficient HHG.
• This method simplifies experimental requirements, avoiding the need for high-contrast lasers.
• The technique holds promise for developing intense extreme ultraviolet sources with high repetition rates.