Off-axis multipass amplifier as a large aperture driver stage for fusion lasers

Area of Science:

• Laser Physics
• Fusion Energy Technology

Background:

• Current large-aperture laser driver stages face limitations with optical switches.
• High-gain amplifier designs are crucial for efficient fusion laser systems.

Purpose of the Study:

• To describe a novel multipass amplifier configuration for large-aperture, high-gain driver stages.
• To investigate and optimize the saturated gain characteristics numerically.
• To experimentally assess potential issues like self-lasing, beam quality, and amplified spontaneous emission.

Main Methods:

• Utilized an off-angle geometry to eliminate the need for optical switches.
• Performed numerical optimization of saturated gain characteristics.
• Conducted experimental investigations into self-lasing, output beam quality, and amplified spontaneous emission.

Main Results:

• The multipass amplifier configuration avoids limitations associated with large aperture optical switches.
• Numerical optimization refined the saturated gain characteristics.
• Experimental results demonstrated comparable performance and cost to linear chain amplifiers, with operational advantages.

Conclusions:

• The described multipass amplifier is a viable alternative for fusion laser driver stages.
• The off-angle geometry effectively bypasses limitations of optical switches.
• The system offers comparable performance and cost with enhanced operational benefits.