Bichromatic Imaging of Single Molecules in an Optical Tweezer Array

Area of Science:

• Molecular Imaging
• Quantum Optics
• Spectroscopy

Background:

• Trapping and detecting single molecules is crucial for quantum science.
• Existing methods face challenges with fidelity and photon budgets.
• Laser cooling of complex molecules requires precise characterization of optical properties.

Purpose of the Study:

• To introduce a novel bichromatic fluorescent imaging scheme for background-free detection of single CaF molecules.
• To achieve high imaging and nondestructive detection fidelities.
• To develop methods for characterizing loss mechanisms in molecular detection.

Main Methods:

• Utilizing a bichromatic laser scheme for simultaneous fluorescence collection and laser cooling.
• Implementing a novel dispersive method to measure transition matrix elements between excited states.
• Characterizing loss mechanisms like two-photon decay and excited-state admixtures.

Main Results:

• Achieved 97.7(2)% imaging fidelity and 95.5(6)% nondestructive detection fidelity.
• Demonstrated high fidelity with a modest photon budget.
• Developed a new technique to measure excited-state transition matrix elements and Franck-Condon factors.

Conclusions:

• The bichromatic imaging scheme offers a promising pathway for sensitive molecular detection.
• The method's efficiency suggests applicability to more complex molecules.
• The developed characterization techniques advance efforts in laser cooling complex polyatomic molecules.