抄録
In this paper, a forced motion of fine solid particles in liquid, induced by a laser beam is discussed. The irradiation of focused laser beam generates the gradient force, which enables to trap fine particles in three dimensions. New phenomena have been observed. One of the phenomena is that the particles around the focus point of the laser beam gathered and then left from the point. Our experimental system contains CW Nd^<+3> : YAG laser, which has 1.064micron in wavelength, and optical microscope. The motion of particles was monitored by a CCD camera on top of the microscope and recorded in VHS.
