Nowadays technologies, especially microelectronics, becomes increasingly powerful and complex by decreasing  the feature sizes down to a few nanometers. At such dimensions small forces can no longer be neglected but significantly influence device operation.

Vacuum fluctuations induce the well known Casimir force leading to irreversible stiction of metallic plates. In binary critical liquids, the analogous critical Casimir forces can be induced due to the density fluctuations (constant de- and remixing) occurring near-criticality.
Optical cavities formed between two boundaries in which light is being reflected multiple times before exiting can provide quantitative analysis of such forces.