Abstract: Apparatus and methods for ultrasonic coupling between a coupling fluid and an object using micro surface tension and capillary effects are provided. The apparatus may include a chamber comprising a wall, a bottom, and a fluid inlet. The fluid inlet may allow a fluid to enter the chamber. Portions of the wall may have a number of slits with dimensions that allow a controlled overflow of the fluid to hold a top surface of the fluid in a stable contact with the object when the fluid is flowing into the chamber. The object may be located at a distance from the top of the wall. Additional apparatus and methods are disclosed.