I have been writing for some time about the technological advances that are being made allowing us to harness the characteristics of light for a multitude of new uses. I’ve even described the 21st Century as being the Century of Light, because of the new discoveries that are being made and the potential those discoveries have for transforming our lives.
This week’s installment is about a technology developed at Harvard’s School of Engineering and Applied Sciences that can make light behave in complex ways: tracing a spiral path like a corkscrew, for example. Called “structured beams” or “structured light”, they can be applied to actually move objects at the nano-scale.
Polarization describes the direction along which light vibrates. That direction can be a circular one. Envision it as beam of light rotating on an axis, as a planet does. But light also has motion in a second direction, which is described as orbital angular momentum. If polarization is like a planet spinning on its axis, orbital angular momentum is like that planet orbiting around a sun. Orbital momentum is strong enough to make microscopic particles move.
What the team at Harvard has done is to create a “meta surface” that can control the spin-orbital motion in any way desired. They describe it as a completely new optical component unlike anything that exists in the natural world.
This technology is going to have significant impact. It will be used in many applications, as yet unforeseen.