Longitudinally excited N₂ laser with large-diameter discharge tube

Area of Science:

• Optics and Photonics
• Laser Physics
• Gas Discharge Physics

Background:

• Achieving high beam quality and high output power in ultraviolet (UV) lasers is challenging.
• Master oscillator power amplifier (MOPA) systems offer a potential solution for high-power laser generation.
• Longitudinally excited gas lasers provide a basis for UV laser development.

Purpose of the Study:

• To develop a MOPA system for a longitudinally excited gas laser to produce high-quality UV laser output.
• To optimize pre-ionization techniques for uniform discharge in a large-diameter gas laser.
• To achieve a quasi-Gaussian beam profile for efficient power amplification.

Main Methods:

• Utilized a MOPA configuration with separate oscillator and amplifier stages.
• Employed a large-diameter (14 mm inner diameter, 30 cm length) dielectric discharge tube for the nitrogen (N₂) laser.
• Optimized pre-ionization by adjusting the gap between the dielectric tube and a surrounding metallic tube.
• Controlled pre-ionization to achieve uniform discharge and a quasi-Gaussian beam profile.

Main Results:

• Achieved a quasi-Gaussian laser beam profile with a correlation factor of 0.99513.
• Obtained a laser pulse energy of 343 μJ.
• Required an input energy of 2.95 J for the discharge.

Conclusions:

• The developed MOPA system effectively produces a high-quality, quasi-Gaussian UV laser beam.
• Optimized pre-ionization is critical for achieving uniform discharge and desired beam characteristics in large-diameter gas lasers.
• The system demonstrates potential for high-power UV laser applications.