An optical levitation and translation method for a microscopic particle by use of the resultant force induced by multiple light beams is studied. We show dependence of the radiation pressure force on the illuminating distribution by numerical calculation, and we find that the strongest axial force is obtained by a specific spacing period of illuminating beams. Extending the optical manipulation technique by means of vertical-cavity surface-emitting laser (VCSEL) array sources [Appl. Opt. <b>40</b>, 5430 (2001)], we are the first, to our knowledge, to demonstrate levitation of a particle and its translation while levitated by using a VCSEL array. The vertical position of the target particle can be controlled in a range of a few tens of micrometers with an accuracy of 2 μm or less. The analytical and experimental results suggest that use of multiple beams is an effective method to levitate a particle with low total illumination power. Some issues on the manipulation method that uses multiple beams are discussed.
© 2002 Optical Society of America
(120.4640) Instrumentation, measurement, and metrology : Optical instruments
(140.3290) Lasers and laser optics : Laser arrays
(140.7010) Lasers and laser optics : Laser trapping
(250.7260) Optoelectronics : Vertical cavity surface emitting lasers
(350.4990) Other areas of optics : Particles
Yusuke Ogura, Nobuhiro Shirai, and Jun Tanida, "Optical Levitation and Translation of a Microscopic Particle by Use of Multiple Beams Generated by Vertical-Cavity Surface-Emitting Laser Array Sources," Appl. Opt. 41, 5645-5654 (2002)