Can low power laser induce dimple on air-water interface?

We investigate deformations of fluid interfaces caused by small (~nN) optical force of a low power laser beam under total-internal-reflection. For air-water interface deformations are undetectable, unlike recently claimed in ref. [3]. Using a critical fluid-fluid interface having weak surface tension large fluid-lens effects in the form of a bump are seen. Our observations support standard optofluidic force-balance with potential for technological applications.