Zeeman-tunable modulation transfer spectroscopy

Area of Science:

• Atomic, Molecular, and Optical (AMO) Physics
• Laser Spectroscopy
• Quantum Technologies

Background:

• Modulation Transfer Spectroscopy (MTS) is a precise laser locking technique.
• Traditional MTS is limited to closed atomic transitions due to its reliance on four-wave mixing.
• This limitation excludes MTS from numerous important AMO physics applications.

Purpose of the Study:

• To report the first observation of a magnetically tunable MTS error signal.
• To overcome the limitations of traditional MTS for laser frequency stabilization.
• To expand the applicability of MTS to a wider range of atomic and molecular resonances.

Main Methods:

• Utilized a simple two-magnet arrangement to induce Zeeman shifts.
• Applied magnetic fields to tune the MTS error signal for Rubidium-87 (Rb87).
• Demonstrated tunability over a range exceeding 15 GHz on the Rb87 D2 spectrum.

Main Results:

• Successfully observed a magnetically tunable MTS error signal for the first time.
• Achieved Zeeman-shifting of the error signal for the Rb87 F=2→F'=3 cooling transition.
• Demonstrated MTS signals for locking to the Rb87 F=1→F'=2 repumping transition and a detuned cooling transition.

Conclusions:

• The developed technique enables laser locking to arbitrary points on the rubidium D2 spectrum.
• This magnetically tunable MTS method significantly broadens the scope of laser stabilization applications.
• The technique is readily extendable to locking Raman and lattice lasers, enhancing precision in AMO experiments.