When light hits your hand, you feel nothing but a rise in temperature. But in fact, light is able to move objects. And before it was only a certain type of laser. But not now.
Back in 1970, physicist Arthur Eshkin described the first principles of the effect of light on objects, and in 2018 he received the Nobel Prize "for the invention of optical tweezers and their application in biological systems." But now scientists from South Africa have finalized this project, and it has become much more versatile.
In ordinary optical traps, light is focused extremely narrowly on a small volume containing a small number of particles, for example, biological cells. At such a micro- or nano-level, the force exerted by the rays of light can be extremely significant, and therefore the cells can literally be caught by light, after which it is possible to control them. Initially, the light was controlled mechanically, but then the project was finalized, as a result of which a holographic optical trap appeared. But until now only certain types of laser beams could be used in it.
Now researchers at the University of the Witwatersrand have shown how it is possible to create and control any pattern of light holographically, and then use that light in new optical traps and tweezers.
In particular, the device can work with traditional laser beams (scalar beams) as well as with more complex vector beams that were simply impossible to use before.
The researchers demonstrated a new trap by holographically controlling both scalar and vector beams in a single device. Such a device can be useful in experiments with micro- and nanoworlds, in the study of single cells and medicine, fundamental physics, and in the creation of future computer chips.