Selective zoning of high harmonic emission using counter-propagating light

Area of Science:

• * Nonlinear Optics
• * Quantum Optics
• * Atomic, Molecular, and Optical Physics

Background:

• * High harmonic generation (HHG) is a key process for producing coherent extreme ultraviolet and X-ray light.
• * Optimizing HHG typically involves managing the coherence length of the laser-matter interaction.
• * Disrupting phase-matched emission is crucial for enhancing HHG yields in extended media.

Purpose of the Study:

• * To investigate a novel method for dramatically increasing high harmonic production.
• * To explore the use of counter-propagating light pulses to control harmonic emission.
• * To demonstrate the potential for significant yield enhancement beyond conventional limits.

Main Methods:

• * Utilizing an interaction region significantly longer than the coherence length.
• * Employing counter-propagating laser pulses to create a standing field modulation.
• * Applying a simple power-law model to design pulse parameters for constructive interference.

Main Results:

• * Counter-propagating light effectively disrupts out-of-phase harmonic emission from specific zones.
• * Standing field modulation leads to predictable phase cancellations.
• * The proposed method can counteract geometrical phase mismatches, improving emission by over two orders of magnitude for individual harmonics.

Conclusions:

• * Counter-propagating pulses offer a powerful tool for controlling and enhancing high harmonic generation.
• * This technique enables constructive buildup of harmonic emission over extended interaction lengths.
• * The findings pave the way for more efficient generation of coherent X-ray light via HHG.