Page "Force spectroscopy" Paragraph 7

Another technique that has been gaining ground for single molecule experiments is the use of optical tweezers for applying mechanical forces on molecules.

A strongly focused laser beam has the ability to catch and hold particles ( of dielectric material ) in a size range from nanometers to micrometers.

The trapping action of optical tweezers results from the dipole or optical gradient force on the dielectric sphere.

The technique of using a focused laser beam as an atom trap was first applied in 1984 at Bell laboratories.

Until then experiments had been carried out using oppositely directed lasers as a means to