Pathway Towards Optical Cycling and Laser Cooling of Functionalized Arenes

TL;DR

This paper investigates the potential for optical cycling and laser cooling of complex arene-based molecules, demonstrating weak vibrational decay pathways that suggest feasibility for quantum control of large molecules.

Contribution

It provides experimental insights into the optical excitation and vibrational branching of large arene molecules, extending the scope of laser cooling techniques to complex molecular structures.

Findings

Weak vibrational decay observed in studied molecules

Potential for full quantum control of large arene molecules

Supports extension of optical cycling to complex molecular systems

Abstract

Rapid and repeated photon cycling has enabled precision metrology and the development of quantum information systems using a variety of atoms and simple molecules. Extending optical cycling to structurally complex molecules would provide new capabilities in these areas, as well as in ultracold chemistry. Increased molecular complexity, however, makes realizing closed optical transitions more difficult. Building on the already established strong optical cycling of diatomic, linear triatomic, and symmetric top molecules, recent theoretical and experimental work has indicated that cycling will be extendable to phenol containing molecules, as well as other asymmetric species. The paradigm for these systems is the use of an optical cycling center bonded to a molecular ligand. Theory has suggested that cycling may be extended to even larger ligands, like naphthalene, pyrene and coronene. Here, we study the optical excitation and vibrational branching of the molecules CaO-2-naphthyl, SrO-2-naphthyl and CaO-1-naphthyl and find only weak decay to excited vibrational states, indicating a promising path to full quantum control and laser cooling of large arene-based molecules.