Engineers demonstrate a new type of optical tweezer

Microfabricated optical tweezer has the potential to make biological and microfluidic force measurements in integrated systems such as microfluidic chips

(a). Photograph of microfabricated Fresnel Zone Plate optical tweezer, consisting of concentric gold rings (50 nm thick) on a microscope slide. The Zone Plate outer diameter is 100¼m, and... Click here for more information.

CAMBRIDGE, Mass. -- February 25, 2008 -- Researchers at the Harvard School of Engineering and Applied Sciences (SEAS) demonstrated a new type of optical tweezer with the potential to make biological and microfluidic force measurements in integrated systems such as microfluidic chips. The tweezer, consisting of a Fresnel Zone Plate microfabricated on a glass slide, has the ability to trap particles without the need for high performance objective lenses.

The device was designed, fabricated, and tested by postdoctoral fellow Ethan Schonbrun and undergraduate researcher Charles Rinzler under the direction of Assistant Professor of Electrical Engineering Ken Crozier (all are affiliated with SEAS). The team's results were published in the February 18th edition of Applied Physics Letters and the researchers have filed a U.S. provisional patent covering this new device.