178  mJ single-frequency nanosecond Tm,Ho:YAG amplifier

Area of Science:

• Laser Physics
• Materials Science

Background:

• Thulium and Holmium-codoped Yttrium Aluminum Garnet (Tm,Ho:YAG) lasers are crucial for generating radiation at 2.09 µm.
• Developing high-energy, single-frequency nanosecond lasers is essential for various scientific and industrial applications.

Purpose of the Study:

• To demonstrate a high-energy, single-frequency nanosecond diode-side-pumped Tm,Ho:YAG laser.
• To design and implement a Master Oscillator and Power Amplifier (MOPA) system for enhanced laser performance.

Main Methods:

• Utilized a diode side-pumping technique for efficient energy transfer.
• Implemented a MOPA configuration comprising a single-frequency seed source, an injection-amplifier with a folded "twisted-mode" cavity, and a two-stage amplifier.
• Employed a heterodyne beating technique for precise linewidth measurement.

Main Results:

• Achieved a maximum single-frequency output energy of 178 mJ.
• Delivered pulses with a pulse width of 235.4 ns at a pulse repetition rate (PRR) of 5 Hz.
• Measured a narrow linewidth of 2.79 MHz and excellent beam quality with M² factors of 1.72 (x-direction) and 1.67 (y-direction).

Conclusions:

• Successfully demonstrated a high-energy, single-frequency nanosecond Tm,Ho:YAG laser operating at 2.09 µm.
• The MOPA system design enabled efficient amplification and high output energy.
• The achieved performance metrics indicate suitability for applications requiring high-power, narrow-linewidth laser sources.