Advanced drive laser system for a high-brightness continuous-wave photocathode electron gun

Area of Science:

• Physics
• Laser Technology
• Particle Accelerators

Background:

• Continuous-wave photocathode electron guns require high-performance drive lasers for enhanced electron beam generation.
• Existing laser systems may lack the necessary power, stability, or control for advanced applications.
• Peking University sought to improve electron beam current and brightness from their photocathode electron gun.

Purpose of the Study:

• To develop a multifunctional drive laser system, PULSE (Peking University drive Laser System for high-brightness Electron source), to enhance photocathode electron gun performance.
• To achieve higher current and brightness electron beams.
• To provide precise control over laser pulse characteristics for electron beam diagnosis.

Main Methods:

• Development of the PULSE system incorporating two stages of photonic crystal fibers for power amplification.
• Integration of two acousto-optic modulators for macro-pulse selection with variable repetition frequencies and duty cycles.
• Implementation of birefringent crystals for temporal pulse shaping and Gaussian pulse stacking.

Main Results:

• The PULSE system reliably delivers 120 W of average output power in infrared laser pulses at 81.25 MHz.
• The system achieves approximately 13.8 W of stable green power output.
• Demonstrated capability for temporal pulse shaping and stacking for customized electron beam generation.

Conclusions:

• The developed PULSE laser system successfully meets the requirements for enhancing photocathode electron gun performance.
• The system's multifunctional capabilities, including high power output and precise pulse control, are crucial for generating high-brightness electron beams.
• Detailed optical schematic and operating performance data are presented, validating the system's effectiveness.