Manipulation of small objects by a laser beam

Abstract

Laser trapping is a very effective method for various minute objects manipulation. If various forms of minute objects can manipulate, assembling of the micro-device is possible. Moreover, if minute reflective objects of metals can manipulate, the production of function material is possible in a limited part. In this paper, the manipulation methods of these minute objects is explained and examined. Three-dimensional manipulation of minute reflective objects is possible in the water. In this method, the laser beam is reformed in a ring-shaped and this ring-shaped laser beam is allowed for irradiation intermittently from the bottom of the minute reflective object. It is observed that the minute reflective object is hold in the fixed position by the laser beam. During this process, convection occurred in the water. The minute reflective object became unstable by the effect of convection. When a surfactant is added, the occurrence of the convection is disappeared and consequently it is possible a stable three dimensional manipulation of minute reflective objects in water. In air, the manipulation of minute objects of various forms is examined. It is observed that a minute rod is changed its posture from the horizontal to vertical position due to the effect of laser irradiation. Moreover, it is also possible to manipulate a minute rod without changing its posture. On the other hand, the manipulation of an object, which is consists of a minute particle and a rod, is also possible. A thin quartz plate in air is successfully manipulated to change its posture from the horizontal to the vertical position.