Transient deformation of liquid surfaces by laser-induced thermocapillarity

Abstract

Heavy hydrocarbons are irradiated with a Gaussian laser beam. The time-varying temperature distribution induced in the fluid gives rise to a surface-tension distribution. The later gives rise in turn to an accompanying liquid flow and surface-height distribution. In this paper, the time-varying shape of the induced depression is calculated as a function of the power distribution in the laser beam and of the thermal and mechanical properties of the material. The intensity distribution in the laser beam reflected from the depression is also calculated. Good agreement is found with previous experimental results.

Dynamics and flow characterization of liquid fountains produced by light scattering

“…The most famous example is thermal Marangoni flow (called optocapillarity when induced by light) due to heat transfer to the interface when a liquid layer absorbs light at the used optical wavelength. It was widely studied experimentally, theoretically and numerically as it is easily induced by a local laser-heating [1][2][3][4]. With the development of microfluidic toolboxes on the one hand, and the enhancement of the surface to volume coupling contributions with miniaturization, on the other hand, many efforts were concentrated towards the developments of optically induced surface-tensiondriven flows at the microscale.…”

Biomimetic optics: liquid-based optical elements imitating the eye functionality

“…In the case of local heating of the layer with the laser beam, the thermocapillary concave deformation in the layer is formed in the heating area, which can serve as a concave liquid mirror [63,64]. It was shown in [64] that the focal length of the thermocapillary mirror, induced by the laser beam in the thin layer on the light-absorbing substrate, can be tuned over a wide range for up to five times by changing the laser power or the layer thickness.…”

Laser‐Induced Crystallization and Crystal Growth

“…Consequently the temperature distribution at the solution surface becomes non‐uniform and results in local surface depression 53. 54 Actually, on measuring the surface deformation with a surface displacement meter, the surface depression started immediately after laser irradiation. The temporal change of the local surface height and the corresponding CCD images are shown in Figure 10 a and 10 b, respectively.…”