Researchers have known for some time of monochromatic light beams, such as Laguerre-Gauss beams, which carry orbital angular momentum also have a helical phase profile. According to Ole Steuernagel of the University of Hertfordshires Science and Technology Research Institute, UK, have helical wave fronts and can be made visible using interferometry. Such dark helices can be generated at higher resolution than light helices and so could be used to etch helical channels through new materials to create a molecular sieve with a left or right handedness for filtering chiral molecules such as pharmaceuticals.
I asked Steuernagel about the next step in this work and he conceded that, “I sort of hop around and am currently working on a peculiar quantum transport phenomenon, not really connected with the helices.” However, he added that, “If I have another idea about the helices I might return to it. I have done a bit of other stuff on what you might call sculpted light fields. So, quite likely I will come back to this.”
“I just like to tinker and play with theory,” he told me. “I am not an experimentalist and so all I can say is, someone will want to use helical light to make handed materials and perhaps the other applications I mentioned. I would be very happy to see my stuff applied. Maybe the underlying message is more important, the one about the resolution limit being circumvented…that and he possibility of dark patterning.”