ASE suppression in a high energy Titanium sapphire amplifier

Area of Science:

• Laser physics
• High-power laser systems
• Nonlinear optics

Background:

• Generating ultrashort pulses with petawatt peak power necessitates amplifiers with large, uniformly pumped gain regions.
• High amplified spontaneous emission (ASE) levels in such amplifiers degrade performance by depleting gain.
• Minimizing transverse gain and internal reflections is crucial for efficient amplification.

Purpose of the Study:

• To develop a high-energy Ti:sapphire amplifier for ultrashort pulse generation.
• To overcome gain depletion caused by amplified spontaneous emission (ASE).
• To improve the performance of petawatt-class laser systems.

Main Methods:

• Utilized beam homogenization techniques to ensure uniform energy distribution.
• Implemented a double-pass pumping scheme for the Ti:sapphire crystal.
• Employed a novel index-matched absorber liquid to minimize internal reflections and parasitic oscillations.
• Developed amplifiers for the Astra Gemini laser system.

Main Results:

• Demonstrated successful suppression of amplified spontaneous emission (ASE).
• Overcame gain depletion issues in a large-aperture, high-energy Ti:sapphire amplifier.
• Achieved high-performance amplification of ultrashort pulses.

Conclusions:

• The combined approach of beam homogenization, double-pass pumping, and index-matched absorbers effectively mitigates ASE.
• This method enables the development of high-energy Ti:sapphire amplifiers for petawatt-class laser systems.
• The Astra Gemini laser system's amplifier performance was significantly improved.