Narrow-linewidth, quasi-continuous-wave ASE source based on a multiple-pass Nd:YAG zigzag slab amplifier...

Area of Science:

• Laser Physics
• Optical Engineering
• Astronomy Instrumentation

Background:

• Developing high-intensity, narrow-linewidth pulsed lasers is crucial for applications like adaptive optics.
• Existing laser sources face challenges with mesospheric sodium atom saturation, limiting guide star brightness.

Purpose of the Study:

• To investigate a novel quasi-continuous-wave pulsed all-solid-state amplified spontaneous emission (ASE) source.
• To optimize the source for high-intensity, narrow-linewidth output suitable for generating brighter sodium guide stars.

Main Methods:

• Utilized a novel multiple-pass zigzag slab amplifier with a Nd:YAG active medium.
• Amplified spontaneous emission (ASE) fluorescence seeded and passed through the slab 8 times.
• End-pumped the Nd:YAG slab using two high-brightness laser diode arrays.

Main Results:

• Achieved a maximum single pulse energy of 347 mJ with ~5.9% optical conversion efficiency.
• Obtained a narrow 3-dB linewidth of 20 pm (5.3 GHz), narrowing with increased pump energy.
• Demonstrated smooth pulses without relaxing spikes and good beam quality (3.5/17).

Conclusions:

• The developed zigzag slab ASE source provides high-intensity, smooth-pulse, and narrow-linewidth output.
• This laser technology effectively addresses mesospheric sodium atom saturation issues.
• The source is highly suitable for creating brighter sodium guide stars for adaptive imaging in astronomy.