Coherent laser-millimeter-wave interactions en route to coherent population transfer

Area of Science:

• Atomic Physics
• Quantum Optics
• Spectroscopy

Background:

• Rydberg states offer unique properties for quantum information and precision measurements.
• Coherent control of atomic populations is crucial for quantum technologies.
• Millimeter-wave spectroscopy provides a sensitive probe for atomic and molecular transitions.

Purpose of the Study:

• To demonstrate and analyze coherent two-photon population transfer to Rydberg states in barium atoms.
• To investigate the role of millimeter-wave radiation in achieving coherence.
• To identify optimal conditions and limitations for population transfer.

Main Methods:

• Utilizing a pulsed dye laser for excitation.
• Employing a chirped-pulse millimeter-wave spectrometer for coherence control.
• Performing numerical calculations with a density matrix formalism.

Main Results:

• Successful demonstration of coherent two-photon population transfer to Rydberg states.
• Numerical models accurately reproduced experimental observations.
• Identified factors influencing fractional population transfer and optimal conditions.
• Highlighted the contribution of long coherence times from millimeter-wave radiation.

Conclusions:

• Coherent population transfer to Rydberg states is achievable using combined laser and millimeter-wave techniques.
• Millimeter-wave coherence is beneficial but limited by laser coherence for advanced schemes.
• Further improvements in laser coherence are necessary for stimulated Raman adiabatic passage and molecular applications.