We report on optical levitation and manipulation of microscopic particles that are stuck on a glass surface with pulsed optical tweezers. An infrared pulse laser at 1.06 µm was used to generate a large gradient force (up to 10^-9 N) within a short duration (∼45 µs) that overcomes the adhesive interaction between the particles and the glass surface. Then a low-power continuous-wave diode laser at 785 nm was used to capture and manipulate the levitated particle. We have demonstrated that both stuck dielectric and biological micrometer-sized particles, including polystyrene beads, yeast cells, and Bacillus cereus bacteria, can be levitated and manipulated with this technique. We measured the single-pulse levitation efficiency for 2.0 µm polystyrene beads as a function of the pulse energy and of the axial displacement from the stuck particle to the pulsed laser focus, which was as high as 88%.
© 2005 Optical Society of America
(140.7010) Lasers and laser optics : Laser trapping
(170.3890) Medical optics and biotechnology : Medical optics instrumentation
(170.4520) Medical optics and biotechnology : Optical confinement and manipulation
Amol Ashok Ambardekar and Yong-qing Li, "Optical levitation and manipulation of stuck particles with pulsed optical tweezers," Opt. Lett. 30, 1797-1799 (2005)