Self-injection locked CW single-frequency tunable Ti:sapphire laser.

Area of Science:

• Laser Physics
• Quantum Optics
• Photonics

Background:

• Continuous-wave (CW) single-frequency tunable lasers are crucial for various scientific applications.
• Achieving stable unidirectional operation in Ti:sapphire lasers presents a significant challenge.
• Self-injection locking offers a potential method for enhancing laser performance.

Purpose of the Study:

• To demonstrate a self-injection locked Ti:sapphire laser with stable unidirectional and single-frequency operation.
• To investigate the impact of output coupler transmission on laser performance.
• To characterize the power, stability, beam quality, and tuning capabilities of the developed laser.

Main Methods:

• Utilizing a retro-reflecting device to induce unidirectional operation via self-injection locking.
• Systematically varying the output coupler transmission to optimize laser performance.
• Employing a pump power of 18 W to achieve maximum output.
• Measuring power stability, beam quality (M²), tuning range, and frequency-tuning ability.

Main Results:

• Stable unidirectional and single-frequency operation was achieved by ensuring a sufficient loss difference between output directions.
• A 6.5% output coupler yielded a maximum of 5 W CW output power.
• Measured power stability was better than ±0.9%, with an M² value of 1.1.
• The laser demonstrated a maximal tuning range of 120 nm and a continuous frequency-tuning ability of 40.75 GHz.

Conclusions:

• The self-injection locked Ti:sapphire laser design successfully achieves stable, unidirectional, and single-frequency operation.
• Output coupler transmission is a critical parameter for optimizing unidirectional operation and output power.
• The demonstrated laser offers high power, excellent stability, good beam quality, and broad tunability, making it suitable for advanced applications.