Multipass amplifiers with self-compensation of the thermal lens

Area of Science:

• Optics and Photonics
• Laser Physics
• Optical Engineering

Background:

• Thermal lensing in laser amplifiers degrades beam quality.
• Existing 4f-based amplifiers are sensitive to thermal lens variations.
• High-quality laser beam output is crucial for many applications.

Purpose of the Study:

• To present a new multipass amplifier architecture.
• To demonstrate its enhanced stability against thermal lensing.
• To achieve superior output beam quality (TEM00).

Main Methods:

• Utilizing a succession of optical Fourier transforms and short propagations.
• Analyzing output beam size and divergence variations using Taylor expansion.
• Investigating effects of thermal lens power, number of passes, and aperture effects.

Main Results:

• The proposed multipass amplifier shows superior stability against thermal lens variations.
• It is robust to changes in the active medium's dioptric power.
• The architecture efficiently uses transverse beam filtering for excellent beam quality.

Conclusions:

• The novel multipass amplifier architecture offers improved thermal stability.
• This design is resilient to variations in the active medium's optical power.
• The architecture provides a robust method for generating high-quality laser beams.