Related Experiment Video
Updated: Apr 22, 2026
08:48
Selective Area Modification of Silicon Surface Wettability by Pulsed UV Laser Irradiation in Liquid Environment
Published on: November 9, 2015
7.7K
Laser induced surface stress on water droplets
Optics Express
|October 17, 2014
Summary
Laser stress on water droplets is investigated. Larger droplets exhibit significantly enhanced forward stress, comparable to Laplace pressure, especially when excited at whispering gallery modes.
Area of Science:
- Physics of fluids
- Laser-matter interactions
- Acoustic and optical phenomena
Background:
- Investigating laser-induced stress on spherical water droplets.
- Focusing on surface stress due to vanishing body stress at mechanical equilibrium.
Purpose of the Study:
- To analyze the directional dependence of surface stress on water droplets of varying sizes.
- To quantify the enhancement of forward stress in larger droplets due to light focusing.
- To explore the conditions for significant stress amplification, comparable to Laplace pressure.
Main Methods:
- Theoretical analysis of laser-induced surface stress on spherical particles.
- Considering sub-wavelength and larger droplet regimes.
- Simulating excitation at whispering gallery modes (Q ~ 10⁴) with a Gaussian beam.
Main Results:
- Surface stress is weaker along the light propagation direction for sub-wavelength droplets.
- Larger droplets show significantly enhanced forward stress due to light focusing.
- For micron-sized droplets excited at whispering gallery modes, stress is enhanced by two orders of magnitude.
Conclusions:
- Laser-induced surface stress is size-dependent and directionally anisotropic.
- Whispering gallery modes can dramatically amplify stress in larger droplets.
- Enhanced stress can reach magnitudes comparable to the Laplace pressure, impacting droplet behavior.
Related Concept Videos
01:22Surface Tension of Fluid
1.9K
Surface tension is a fundamental property of fluids, occurring at the boundary between a liquid and a gas or between two immiscible liquids. This phenomenon arises from the cohesive forces between molecules at the fluid's surface, creating an effect similar to a stretched elastic membrane. Inside each fluid, molecules are equally attracted in all directions by neighboring molecules, but surface molecules experience a net inward force, resulting in surface tension.
Surface tension varies...
Surface tension varies...
1.9K
02:57Surface Tension, Capillary Action, and Viscosity
28.5K
Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
28.5K
01:04Hydrostatic Pressure Force on a Curved Surface
1.5K
Hydrostatic pressure on curved surfaces is a fundamental concept in fluid mechanics with broad applications in the civil engineering field. When fluid is in contact with a curved surface, as in a reservoir, dam, or storage tank, it exerts pressure that varies in magnitude and direction along the curved surface. To assess the total hydrostatic force exerted by the fluid on a curved structure, engineers typically isolate the fluid volume adjacent to the surface and analyze the forces acting on...
1.5K
01:16Surface Tension and Surface Energy
3.2K
When a paint brush is immersed in water, the bristles wave freely inside the water. When it is taken out, the bristles stick together. The reason behind this effect is surface tension.
Consider a beaker filled with liquid. The bulk molecules in the liquid experience equal attractive forces on all sides with the surrounding molecules. However, the surface molecules experience a net attractive force downward due to the bulk molecules. The surface of the liquid behaves like a stretched membrane,...
Consider a beaker filled with liquid. The bulk molecules in the liquid experience equal attractive forces on all sides with the surrounding molecules. However, the surface molecules experience a net attractive force downward due to the bulk molecules. The surface of the liquid behaves like a stretched membrane,...
3.2K
01:13Excess Pressure Inside a Drop and a Bubble
3.5K
The shape of a small drop of liquid can be considered spherical, neglecting the effect of gravity. This drop can further be considered as two equal hemispherical drops put together due to surface tension. The forces acting on the spherical drop are due to the pressure of the liquid inside the drop, the pressure due to air outside the drop, and the force due to the surface tension acting on the two hemispherical drops.
3.5K
01:04Hydrostatic Pressure Force on a Plane Surface
3.1K
When a plane surface is submerged in a fluid, hydrostatic forces develop on the surface due to the fluid's pressure. For horizontal surfaces, the pressure exerted by the fluid is uniform because the depth remains constant. The resultant force is determined by the pressure at the given depth multiplied by the area of the surface, and it acts through the centroid of the surface. For vertical surfaces, the pressure varies with depth, increasing as the distance from the fluid's free surface...
3.1K