Optical two-dimensional coherent spectroscopy of cold atoms

Area of Science:

• Atomic, Molecular, and Optical (AMO) Physics
• Quantum Spectroscopy
• Condensed Matter Theory

Background:

• Two-dimensional coherent spectroscopy (2DCS) is a powerful technique for probing complex quantum systems.
• Applying 2DCS to cold atoms presents unique challenges and opportunities for studying quantum phenomena.

Purpose of the Study:

• To experimentally demonstrate optical 2DCS in a cold atomic system.
• To establish a foundation for investigating many-body physics and chemical dynamics in ultracold atoms, atom arrays, and trapped ions.

Main Methods:

• Integration of a collinear 2DCS setup with a magneto-optical trap (MOT).
• Preparation of cold rubidium (Rb) atoms at ~200 µK and 10^10 cm^-3 density.
• Utilizing femtosecond laser pulses to generate one-dimensional nonlinear signals and acquire 2D spectra (one-quantum and zero-quantum).

Main Results:

• Successful experimental demonstration of optical 2DCS in cold Rb atoms.
• Acquisition of both one-quantum and zero-quantum 2D spectra.
• Characterization of nonlinear optical signals (second and fourth order).

Conclusions:

• Optical 2DCS in cold atoms is achievable and represents a significant advancement.
• This technique opens new pathways for exploring many-body physics in cold atoms and trapped ions.
• It also offers a novel approach for studying chemical reaction dynamics in cold molecules.