Optical phase locking of two infrared continuous wave lasers separated by 100  THz

Area of Science:

• Optics and Photonics
• Laser Physics

Background:

• Continuous wave (CW) infrared (IR) laser sources are crucial for various spectroscopic applications.
• Achieving precise frequency control and high output power in laser systems remains a significant challenge.

Purpose of the Study:

• To demonstrate phase locking of two distinct CW IR laser sources with a 100 THz frequency separation.
• To develop a compact frequency comb with enhanced output power compared to existing technologies.

Main Methods:

• Utilized three independent harmonic generation processes in periodically poled MgO:LiNbO3 crystals.
• Generated second and third harmonics of 1029 nm and 1544 nm IR laser frequencies.
• Employed the beat note between generated green radiations (~515 nm) for phase locking with tunable radio frequency offset.

Main Results:

• Successfully achieved phase locking between the two IR laser sources.
• Demonstrated a mini-frequency comb emitting four intense optical radiations at 1544 nm, 1029 nm, 772 nm, and 515 nm.
• Achieved output powers significantly higher (at least three orders of magnitude) than individual modes from femtosecond lasers.

Conclusions:

• The developed method provides a robust way to phase lock IR laser sources.
• The mini-frequency comb offers a high-power, compact alternative for applications requiring precise optical frequencies.
• This technique advances the generation of tunable, high-intensity optical radiation.