High-contrast plasma-electrode Pockels cell

Area of Science:

• Laser-induced fusion and high-power laser systems.
• Optical physics and materials science.
• Plasma physics and engineering.

Background:

• High-power laser systems require effective optical switches for isolation.
• Plasma-electrode Pockels cells (PEPCs) are utilized for optical switching.
• OMEGA EP laser system demands high-contrast isolation for retroreflected pulses.

Purpose of the Study:

• To develop and characterize a PEPC for the OMEGA EP laser system.
• To achieve high-contrast optical switching for system isolation.
• To investigate the impact of window mounting and operating pressure on PEPC performance.

Main Methods:

• Development of a PEPC utilizing circular windows supported on compliant O rings.
• Testing under vacuum loading conditions to assess stress-induced birefringence.
• Evaluation of contrast ratios across the clear aperture.
• Analysis of PEPC operation at various pressures to determine optimal conditions.

Main Results:

• Contrast ratios reliably exceeded 500:1 across the clear aperture.
• The use of compliant O rings significantly reduced stress-induced birefringence under vacuum.
• Reliable operation was achieved at higher operating pressures.
• Low operating pressures correlated with local plasma density loss.

Conclusions:

• The developed PEPC provides effective high-contrast optical switching for the OMEGA EP laser system.
• The innovative window mounting technique is crucial for minimizing optical aberrations.
• Optimized operating pressure is essential for stable plasma density and reliable PEPC performance.