On optical forces in spherical whispering gallery mode resonators

TL;DR

This paper investigates how optical forces in spherical whispering gallery mode resonators are affected by dipole interactions, revealing non-conservative forces and proposing generalized formulas consistent with Maxwell stress tensor calculations.

Contribution

It demonstrates that cavity mode modifications alter optical force properties, showing all force components are non-conservative and providing a generalized force formula.

Findings

All force components are non-conservative.

Standard formulas are generalized to match Maxwell stress tensor results.

Interaction significantly modifies cavity mode properties.

Abstract

In this paper we discuss the force exerted by the field of an optical cavity on a polarizable dipole. We show that the modification of the cavity modes due to interaction with the dipole significantly alters the properties of the force. In particular, all components of the force are found to be non-conservative, and cannot, therefore, be derived from a potential energy. We also suggest a simple generalization of the standard formulas for the optical force on the dipole, which reproduces the results of calculations based on the Maxwell stress tensor.