title: Enhanced formation of a confined nano-water meniscus using a 780 nm laser with a quartz tuning fork-atomic force microscope.
abstract: Demonstrated herein is the optical-field-induced enhancement of the formation of a confined nanowater meniscus using a distance-regulated quartz tuning fork-atomic force microscope (QTF-AFM) with a 780 nm laser. While a pulled optical fiber tip approaches the surface, the laser is suddenly turned on and focuses on the front spot of the tip by the shape of the pulled optical fiber, which plays the role of an objective lens and induces the gathering effect of the water molecules directed to the electromagnetic-field gradient in air. This phenomenon facilitates a new boundary condition to form a long-range confined nano-scale liquid bridge between the tip and the surface. After the pulling of the optical fiber, 20-nm-thick gold was sputtered on the apex (diameter: approximately 100 nm) of the tip to guide and focus the beam on the spot. The critical power of the laser to overcome the barrier for the formation of a new boundary is 100 microW at the distance of 22 nm from the substrate.
authors.affiliation: Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Republic of Korea.
authors.forename: Sangmin
authors.initials: S
authors.lastname: An
authors.forename: Kunyoung
authors.initials: K
authors.lastname: Lee
authors.forename: Geol
authors.initials: G
authors.lastname: Moon
authors.forename: Wan
authors.initials: W
authors.lastname: Bak
authors.forename: Gunn
authors.initials: G
authors.lastname: Kim
authors.forename: Wonho
authors.initials: W
authors.lastname: Jhe