Pushing objects with laser light
When light lands on a surface, it generally exerts a force that is imperceptible to humans. But that hasn’t stopped scientists from tapping this weak force. Specialists in the modern field of optomechanics, which studies the effects of electromagnetic radiation on mechanical motion, are learning to use laser light to control the motion of certain solid objects.
Dr. Jack Sankey, Canada Research Chair in Experimental Optomechanics, is combining state-of-the-art optical systems with high-quality mechanical systems. This allows an incredibly weak source of light — even one that is a million times dimmer than a keychain LED — to profoundly influence the motion of an object large enough to see with our eyes and hold in our fingers.
Perhaps surprisingly, light can control the motion of objects ranging from kilogram-scale mirrors that hang in gravitational wave detectors to nanoscopic-scale mechanical systems that are manufactured on microchips. The intensity and frequency of light can be used to tune the mechanical characteristics of such devices.
Sankey’s research could lead to the development of new optically-controlled mechanical devices in which the solid, flexible support structures are replaced entirely by photons. Because the behavior of photons is fundamentally different from that of atoms in a solid, such devices should achieve unprecedented levels of performance in a variety of applications.