Roto-translational optomechanics

TL;DR

This paper reviews the emerging field of levitated optomechanics focusing on the complex roto-translational motion of anisotropic particles, highlighting theoretical, experimental advances, and potential applications in quantum sensing and fundamental physics.

Contribution

It provides a comprehensive overview of classical and quantum descriptions of roto-translational motion in levitated optomechanics, emphasizing new interactions and experimental techniques.

Findings

Classical and quantum models of roto-translational motion

Experimental methods for controlling anisotropic particles

Potential for quantum-limited torque sensing

Abstract

Levitated optomechanics, the interaction between light and small levitated objects, is a new macroscopic quantum system that is being used as a testing ground for fundamental physics and for the development of sensors with exquisite sensitivity. The utility of this system, when compared to other quantum optomechanical systems, is its extreme isolation from the environment and, by the relatively few degrees of freedom that a levitated object has. While work in the field has strongly focused on the three translational degrees of freedom of this system, it has become increasingly important to understand the induced rotational motion of levitated objects, particularly in optical trapping fields, but also in magnetic and electric traps. These additional three degrees of freedom, which are intrinsic to levitated systems, offer a new set of optomechanical nonlinear interactions that lead to a rich and yet largely unexplored roto-translational motion. The control and utilization of these interactions promise to extend the utility of levitated optomechanics in both fundamental studies and applications. In this review, we provide an overview of levitated optomechanics, before focusing on the roto-translational motion of optically levitated anisotropic objects. We first present a classical treatment of this induced motion, bridging the gap between classical and quantum formalisms. We describe the different types of roto-translational motion for different particle shapes via their interaction with polarized optical trapping fields. Subsequently, we provide an overview of the theoretical and experimental approaches as well as applications that have established this new field. The review concludes with an outlook of promising experiments and applications, including the creation of non-classical states of roto-translational motion, quantum-limited torque sensing and particle characterization methods.