Low-noise, tunable diode laser for ultra-high-resolution spectroscopy

Area of Science:

• Atomic, Molecular, and Optical Physics
• Laser Spectroscopy
• Quantum Optics

Background:

• Diode lasers are crucial for various scientific applications, but achieving high frequency stability and tunability simultaneously remains a challenge.
• Existing laser stabilization techniques often involve complex setups or compromise on performance metrics like linewidth or locking range.

Purpose of the Study:

• To demonstrate a diode laser setup merging resonant optical feedback and grating stabilization for superior spectral properties.
• To characterize the short-term frequency stability and phase-locking capabilities of the developed laser system.

Main Methods:

• Combining diode laser with resonant optical feedback and grating stabilization.
• Characterizing short-term linewidth by beating two identical diode lasers.
• Achieving phase locking using an analog phase detector and a servo loop.

Main Results:

• Achieved a short-term linewidth of approximately 11 kHz.
• Demonstrated cycle-slip-free phase locking for extended periods (many 10 min) with a small servo bandwidth (46 kHz).
• Maintained optical power within a narrow spectral window (< 20 mHz) relative to the optical reference.

Conclusions:

• The demonstrated diode laser concept offers excellent tunability, short-term frequency stability, and controllability.
• The laser system's performance makes it highly suitable for atomic/molecular coherence experiments requiring precise laser phase locking.
• This technology can serve as a critical component in advanced optical clock systems.