7kW direct-liquid-cooled side-pumped Nd:YAG multi-disk laser resonator

Area of Science:

• Laser Physics
• Materials Science
• Optical Engineering

Background:

• High-power pulsed lasers are crucial for various scientific and industrial applications.
• Efficient thermal management is a key challenge in scaling laser power and maintaining beam quality.
• Nd:YAG (Neodymium-doped Yttrium Aluminum Garnet) lasers are widely used due to their favorable properties.

Purpose of the Study:

• To develop and characterize a direct-liquid-cooled, side-pumped Nd:YAG multi-disk laser resonator.
• To investigate the performance of the laser at high pulse energies and average output powers.
• To evaluate the thermal effects and wavefront distortion within the gain module.

Main Methods:

• Utilizing a multi-disk resonator design with twenty thin Nd:YAG disks.
• Implementing direct cooling of disk end surfaces using flowing deuteroxide.
• Employing side-pumping with laser diode (LD) arrays.
• Measuring laser output energy, pulse width, repetition rate, efficiency, and wavefront distortion.

Main Results:

• Achieved a maximum pulse energy of 17.04 J at a 250 μs pulse width and 25 Hz repetition rate.
• Obtained a maximum average output power of 7.48 kW at a 500 Hz repetition rate.
• Reported optical-optical efficiencies of 34.1% (peak) and 30% (at max power due to thermal effects).
• Measured a low wavefront distortion (0.256 μm RMS) under high pumping conditions.

Conclusions:

• The direct-liquid-cooled multi-disk architecture is effective for high-power Nd:YAG laser operation.
• The design demonstrates high efficiency and manageable thermal effects for pulsed laser applications.
• Further optimization can enhance performance and beam quality for demanding laser systems.