From gyroscopic to thermal motion: a crossover in the dynamics of molecular superrotors

Abstract

Localized heating of a gas by intense laser pulses leads to interesting acoustic, hydrodynamic and optical effects with numerous applications in science and technology, including controlled wave guiding and remote atmosphere sensing. Rotational excitation of molecules can serve as the energy source for raising the gas temperature. Here, we study the dynamics of energy transfer from the molecular rotation to heat. By optically imaging a cloud of molecular superrotors, created with an optical centrifuge, we experimentally identify two separate and qualitatively different stages of its evolution. The first non-equilibrium "gyroscopic" stage is characterized by the modified optical properties of the centrifuged gas - its refractive index and optical birefringence, owing to the ultrafast directional molecular rotation, which survives tens of collisions. The loss of rotational directionality is found to overlap with the release of rotational energy to heat, which triggers the second stage of thermal expansion. The crossover between anisotropic rotational and isotropic thermal regimes is in agreement with recent theoretical predictions and our hydrodynamic calculations.

References in corpus (5)

• Higher-order Kerr terms allow ionization-free filamentation in gases
• Effects of ultrafast molecular rotation on collisional decoherence
• Coherent spin-rotational dynamics of oxygen super rotors
• Sound emission from the gas of molecular superrotors
• Inhibited, Explosive and Anisotropic Relaxation in a Gas of Molecular Super-Rotors

Cited by in corpus (15)

• Quantum control of molecular rotation
• RichMol: A general variational approach for rovibrational molecular dynamics in external electric fields
• Climbing the rotational ladder to chirality
• Field-free long-lived alignment of molecules in extreme rotational states
• Ultrafast magnetization of a dense molecular gas with an optical centrifuge
• Observation of mechanical Faraday effect in gas media
• Capture into resonance and phase space dynamics in optical centrifuge
• Quantum versus classical dynamics in the optical centrifuge
• Giant Polarization Drag in a Gas of Molecular Superrotors
• Echoes in Unidirectionally Rotating Molecules
• Rotational Alignment Decay and Decoherence of Molecular Superrotors
• Laser control of molecular rotation: Expanding the utility of an optical centrifuge
• Controlling rotation in the molecular-frame with an optical centrifuge
• Nonlinear dynamics of molecular superrotors
• State- and molecule-selective rotational control in gas mixtures with a shaped optical centrifuge