Control of Molecular Rotation in Helium Nanodroplets with an Optical Centrifuge

Area of Science:

• Quantum dynamics
• Superfluid physics
• Molecular spectroscopy

Background:

• Helium nanodroplets provide a unique environment for studying molecular properties.
• Controlling molecular rotation is crucial for understanding molecular dynamics.
• Superfluid helium presents a complex many-body system for physical investigations.

Purpose of the Study:

• To demonstrate experimental control over molecular rotation within helium nanodroplets using an optical centrifuge.
• To investigate molecular dynamics in the superfluid helium environment at controlled rotational excitation levels.
• To study the rotational behavior of nitric oxide dimers ((NO)2) under optical centrifuge influence.

Main Methods:

• Employing an optical centrifuge to induce and control molecular rotation.
• Doping helium nanodroplets with nitric oxide dimers ((NO)2).
• Measuring time-resolved alignment of (NO)2 molecules to monitor rotational dynamics.

Main Results:

• Demonstrated forced in-field rotation of molecules across a continuous frequency range.
• Observed field-free resonant rotation of molecules with nanosecond-scale decay.
• Quantified the degree of centrifuge-induced molecular alignment as a function of time.

Conclusions:

• Optical centrifuges effectively control molecular rotation in superfluid helium.
• This technique enables the study of molecular dynamics within a superfluid many-body system.
• Findings may offer insights into superfluidity and atom-level superfluid-defect interactions.