Abstract View
Optical-Trapping of Particles in Air Using Parabolic Reflectors and a Hollow Laser Beam: From Submicron to Supermicron Aerosol
AIMABLE KALUME, Jessica Arnold, Yong-Le Pan, U.S. Army Research Laboratory
Abstract Number: 194
Working Group: Instrumentation and Methods
Abstract
We present an advanced optical-trapping method that is capable of trapping arbitrary shapes, any properties (transparent and absorbing) and sized from nanometer to super micron particles in air. Two parabolic reflectors were used to reflect the inner and outer parts of a single hollow laser beam, respectively, to form two counter-propagating conical beams and bring them into a focal point for trapping. This novel design demonstrated high trapping efficiency and strong trapping robustness with a simple optical configuration. Instead of using expensive microscope objectives, the parabolic reflectors not only achieved large numerical aperture (N.A.) focusing, but were also able to focus the beam far away from optical surfaces to minimize optics contamination. This design also offered a large free space for flexible integration with other measuring techniques, such as optical-trapping Raman spectroscopy, for on-line single-particle characterization.