Optical trapping and critical Casimir forces

TL;DR

This paper reviews how optical tweezers are used to experimentally measure critical Casimir forces between colloidal particles, which are significant at nanometer to micrometer scales, with implications for nanotechnology and self-assembly.

Contribution

It provides a comprehensive overview of the application of optical tweezers in studying critical Casimir forces, highlighting their role in advancing nano- and microscale device fabrication.

Findings

Optical tweezers enable precise measurement of critical Casimir forces.

Critical Casimir forces can reach hundreds of nanometers in range.

Use of optical tweezers facilitates development of nano-technologies.

Abstract

Critical Casimir forces emerge between objects, such as colloidal particles, whenever their surfaces spatially confine the fluctuations of the order parameter of a critical liquid used as a solvent. These forces act at short but microscopically large distances between these objects, reaching often hundreds of nanometers. Keeping colloids at such distances is a major experimental challenge, which can be addressed by the means of optical tweezers. Here, we review how optical tweezers have been successfully used to quantitatively study critical Casimir forces acting on particles in suspensions. As we will see, the use of optical tweezers to experimentally study critical Casimir forces can play a crucial role in developing nano-technologies, representing an innovative way to realize self-assembled devices at the nano- and microscale.