Relativistic plasma shutter for ultraintense laser pulses

Area of Science:

• Plasma physics
• High-intensity laser-matter interactions

Background:

• High-intensity laser systems often suffer from a low-intensity pedestal preceding the main pulse.
• This pedestal can prematurely interact with targets, degrading experimental results.
• Improving laser temporal contrast is crucial for precision applications.

Purpose of the Study:

• To propose and experimentally validate a relativistic plasma shutter technique.
• To mitigate the detrimental effects of the laser pulse pedestal.
• To enhance the temporal contrast of high-intensity laser pulses.

Main Methods:

• Utilizing an ultrathin foil as a plasma shutter placed before the target.
• Employing the leading edge of the laser to ionize the foil, creating an underdense plasma.
• Analyzing accelerated proton spectra and directionality to assess temporal contrast improvement.
• Conducting supporting hydrodynamic and particle-in-cell simulations.

Main Results:

• Demonstrated effective removal of the sub-100 picosecond pedestal.
• Observed enhanced laser temporal contrast through characteristic signatures in proton diagnostics.
• Validated the plasma shutter mechanism with advanced simulations.

Conclusions:

• The relativistic plasma shutter is a viable technique for improving laser temporal contrast.
• This method allows the main laser pulse to propagate while rejecting the pedestal.
• The technique shows promise for applications requiring high temporal contrast laser pulses.