Carrier frequency modulation of an acousto-optic modulator for laser stabilization

Area of Science:

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

Background:

• Laser frequency stabilization is crucial for precision measurements in AMO physics.
• Existing methods often rely on specific atomic structures or are sensitive to laser noise.
• A need exists for a versatile and robust laser stabilization technique.

Purpose of the Study:

• To present a novel method for laser wavelength stabilization using frequency modulation.
• To demonstrate its versatility for both atomic and cavity-based systems.
• To validate the method with a specific atomic transition.

Main Methods:

• Utilized frequency modulation of an acousto-optic modulator's drive signal to generate two spatially separated beams with a small frequency difference.
• Employed these beams to probe a narrow absorption feature.
• Generated a dispersion-like signal from the difference in detected signals for wavelength stabilization.

Main Results:

• Successfully demonstrated a novel, simple, and versatile method for diode laser wavelength stabilization.
• Locked an external cavity diode laser to the ⁸⁵Rb 5S_1/2 → 5P_3/2, F = 3 → F' = 4 transition using sub-Doppler pump probe spectroscopy.
• Showed excellent agreement between experimental measurements and a theoretical model.

Conclusions:

• The presented frequency modulation technique offers a robust and adaptable approach to laser stabilization.
• Its requirement for only a narrow absorption line makes it broadly applicable.
• The method shows promise for advancing precision measurements in various optical physics applications.