The problem of light scattering by dielectric particles has a long history. In 2004, scientists proved that the internal focus on the shadow surface of particles of a certain size with certain refractive index shifts to its edge where a highly-localized electromagnetic field appears.
This "photonic nanojet" has a specific cross-dimension (smaller than the diffraction limit) that makes high resolution possible.
"We have managed to receive a new type of curved light beam and have patented the principle we used to create it based on the photonic nanojet formed by asymmetric dielectric particles. During our experiments, we used cuboids with an adjacent prism to create the beam. When radiation falls on the end of the particle, there is diffraction on the edges and inside so the beam becomes curved," explains Professor Igor Minin of Electronic Engineering Department at Tomsk Polytechnic University.
The scientists examined interesting applications for the "photonic hook:" it turns out that it can be used for moving nanoparticles and microscopic objects, such as bacteria, around or above obstacles using light.
"This is very promising for biology and medicine as well as for creating new materials when cell manipulation is necessary," Igor Minin noted.
These nanojets can be used for studying microbes and nano-objects, which are difficult to manipulate. Unlike the beams that require bulky and complex equipment, the "photonic hook" can be produced with lasers and nanoparticles from common glass.