THE MANIPULATING OF SiO2 AND MODIFIED SiO2 PARTICLES IN ATMOSPHERE BY LASER RADIATION PRESSURE

The cohesive and non-spherical particles were trapped in atmosphere by the radiation pressure. The samples were particles that were SiO2, Si3N4, and modified SiO2 by Rhodamine B. The two kinds of trapping systems equipped with Ar+ laser (488nm, TEM00) were used with the lenses of 50mm or 25mm focus length, respectively. The trapping positions were 2.5 +/- 0.5mm above the focus at the laser power more than 100mw with the lens of 50mm focus length. There were equal in the size of beam diameters at the positions of particles that were trapped by 50mw laser power with the lenses of 50mm or 25 mm focus length. The trapping particles got near the focus with decreasing the laser power from 100mw. The trapping positions of the modified SiO2 particles with change of the adsorbed quantity of Rhodamine B depended on the laser power, but were independent of the adsorbed quantities of Rhodamine B.