Wideband laser locking to an atomic reference with modulation transfer spectroscopy

Area of Science:

• Atomic Physics
• Spectroscopy
• Laser Technology

Background:

• Laser frequency stabilization is crucial for precision measurements in atomic physics.
• Conventional modulated spectroscopy often has limitations in noise suppression bandwidth.
• Existing methods like electro-optic modulation have demonstrated single lock-point spectra.

Purpose of the Study:

• To enhance conventional modulated spectroscopy apparatus for wideband laser frequency stabilization.
• To achieve deep suppression of frequency noise across the acoustic range.
• To demonstrate a novel method for improving laser lock performance.

Main Methods:

• Utilizing an acousto-optic modulator driven by an agile oscillator.
• Implementing wideband frequency modulation of the pump laser in modulation transfer spectroscopy.
• Achieving a laser lock with a 100 kHz feedback bandwidth.

Main Results:

• Demonstrated a wideband lock delivering deep suppression of frequency noise (30 dB) across the acoustic range.
• Produced a unique single lock-point spectrum, similar to electro-optic modulation.
• Narrowed the imputed laser linewidth by a factor of five.

Conclusions:

• Enhanced modulated spectroscopy with acousto-optic modulation provides a robust method for wideband laser frequency stabilization.
• This technique offers significant improvements in noise reduction and linewidth narrowing for atomic physics applications.
• The achieved bandwidth is sufficient for substantial noise suppression in the acoustic frequency range.