Holographic study of laser-induced liquid surface deformations

Marangoni convection-driven laser fountains on free surfaces of liquids

“…1k, 1m and 1n) (2,3,10,14). We note that the magnitude of this effect is qualitatively different than previously reported surface depressions, which were too weak to be directly observed by the naked eye or ordinary photography (10,(17)(18)(19)(20)(21). To understand these distinct deformations between deep and shallow liquids, we varied the liquid layer thickness while keeping the laser beam the same.…”

“…More rigorous theoretical treatments (9)(10)(11)(12)(13)(14)(15)(16) and controlled experiments (10,(17)(18)(19)(20)(21) were performed later with non-uniform surface tension created by either substrate heating or surface radiative heating. Besides these fundamental investigations, more cases have been investigated in enormous applications involving liquids or soft matters such as lithography and 3D printing (22)(23)(24), heat transfer and mass transport (19), crystal growth and alloy welding (25,26), dynamic grating and spatial light modulator (15,27), microfluidics and adaptive optics (19,(28)(29)(30).…”

“…This understanding is confirmed by the CFD simulations. Ferrofluid is not a unique liquid for Marangoni convection, a liquid's strong optical absorption can be achieved by varying the laser wavelength, or adding light absorbing elements such as colorants or plasmonic nanoparticles (18,35). Besides fundamental research, Marangoni effect has already found enormous applications in nearly all branches of engineering due to the ubiquitous involvement of liquids (19,(28)(29)(30), the optical manipulation of fluids and fluid surface through Marangoni effect is expected to open new opportunities for novel applications.…”

Laser-Induced Marangoni Convection in the Presence of Surfactant Monolayers

“…In such experiments, the surface of the liquid is deformed due to convection currents induced by laser heating, thus acting as a concave mirror and focusing the beam reflected from the surface as well as information on the surface profile . Laser-induced Marangoni convection has also been used to study capillary waves, − which are of interest for the welding industry since Marangoni convection can affect the weld pool shape in different ways, , and the consequent production of ripples during laser welding may cause significant roughness of the surface of the treated material .…”

“…11 From analyses of the diffraction patterns produced on the reflected beam it is possible to obtain properties of the liquids such as the refractive index, 12 as well as information on the surface profile. 13 Laser-induced Marangoni convection has also been used to study capillary waves, [14][15][16] which are of interest for the welding industry since Marangoni convection can affect the weld pool shape in different ways, 17,18 and the consequent production of ripples during laser welding may cause significant roughness of the surface of the treated material. 19 Experiments on laser-induced Marangoni convection have also been performed in microgravity environments to minimize the influence of buoyancy effects.…”