“In previous work, the researchers discovered that when optical matter is exposed to circularly polarized light, it rotates as a rigid body in the direction opposite the polarization rotation. In other words, when the incident light rotates one way the optical matter array responds by spinning the other. This is a manifestation of “negative torque”. The researchers speculated that a machine could be developed based on this new phenomenon.

In the new work, the researchers created an optical matter machine that operates much like a mechanical machine based on interlocking gears. In such machines, when one gear is turned, a smaller interlocking gear will spin in the opposite direction. The optical matter machine uses circularly polarized light from a laser to create a nanoparticle array that acts like the larger gear by spinning in the optical field. This “optical matter gear” converts the circularly polarized light into orbital, or angular, momentum that influences a nearby probe particle to orbit the nanoparticle array (the gear) in the opposite direction.”

Researchers have developed a tiny new machine that converts laser light into work. These optically powered machines self-assemble and could be used for nanoscale manipulation of tiny cargo for applications such as nanofluidics and particle sorting.

“Our work addresses a long-standing goal in the nanoscience community to create self-assembling nanoscale machines that can perform work in conventional environments such as room temperature liquids,” said research team leader Norbert F. Scherer from the University of Chicago.