Optical trap using a focused hollow-beam for trapping and holding both absorbing and non-absorbing airborne particles

Abstract

Embodiments of the present invention are directed to systems and methods for trapping and holding airborne particles. In the various embodiments, an optical trap is provided which uses a focused hollow-beam for trapping and holding both absorbing and non-absorbing airborne particles. The optical trap comprises: a trapping region where a particle can be present to be trapped; a light source for generating a coherent beam of light; optics for forming a hollow beam having a ring geometry from the coherent beam of light; and a focusing element for focusing the hollow beam to a point in the trapping region. In this arrangement, the particle is trapped at or near the focal point of the focused hollow beam.

Description

GOVERNMENT INTEREST[0001]The invention described herein may be manufactured, used and licensed by or for the U.S. Government without the payment of royalties thereon.[0002]Research underlying this invention was supported by the Defense Threat Reduction Agency (DTRA) under contract numbers HDTRA1310184 and HDTRA1514122, with U.S. Army Research Laboratory mission funds under Cooperative Agreement Number W911NF-12-2-0019.BACKGROUND OF THE INVENTION[0003]1. Field[0004]Embodiments of the present invention are generally directed to trapping and holding airborne particles, and more particularly, to optical traps which use a focused hollow-beam for trapping and holding both absorbing and non-absorbing airborne particles.[0005]2. Description of Related Art[0006]Airborne particles pose many problems. The ability to trap airborne particles for inspection and / or measurement is important for many applications. Conventional techniques to optically trap airborne particles use either radiative pres...

AI Technical Summary

Benefits of technology

The present invention provides devices, systems, and methods for trapping and holding airborne particles using an optical trap. The optical trap uses a focused hollow-beam for trapping and holding both absorbing and non-absorbing airborne particles. The optical trap can detect and measure properties of the trapped particles, and can release them for further use. The system can also continuously sample particles from air and determine parameters related to their shape, size, refractive index, absorption, molecular structures, and compositions. The technical effects of the invention include improved trapping and measuring of airborne particles with high accuracy and efficiency.

Problems solved by technology

Airborne particles pose many problems.

Trapping a particle in air is more difficult than trapping a particle in a liquid (or on a substrate) since the trap must overcome gravity and air turbulence without help from the higher viscosity of a liquid.

Existing photophoretic force based traps are only capable of trapping absorbing particles while existing laser tweezer systems can only trap non-absorbing particles.

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