Justas Berškys, a researcher at the FTMC Department of Optoelectronics, has earned his PhD in Natural Sciences. On 18 April, he defended his doctoral thesis titled "Investigation of Structured Light Topologies and its Lorenz-Mie Scattering". His academic supervisor was Dr Sergejus Orlovas.
Congratulations to Justas – we wish him continued success and discoveries ahead!
As the physicist explains, his dissertation focuses on structured light – in simple terms, light whose properties have been specially “arranged” or “structured”. This means that its beams have a specific shape, direction, twist, or other arrangement, rather than propagating in a random or uniform manner. These controlled properties are intended for carrying out specific experiments.
In his work, this light is described in terms of characteristics such as colour, polarisation (the direction of the light wave’s oscillation), phase (the wave’s "position" in time or space), and amplitude (the wave’s strength).
"By carefully selecting these parameters, we can create light structures that are rotating, curved, or shaped like a ‘bottle’. I studied the propagation of such light, its internal structure, and its interaction with nanoparticles, " says J. Berškys.
According to the researcher, this kind of special light has many practical applications:
"Structured light allows us to develop technologies that help detect compositional changes in the environment (for example, gas leaks), create new tissue and material imaging methods, and increase data transmission rates – both in fibre-optic systems and in free space. It also enables the creation of optical tweezers to manipulate nanoparticles and contributes to the advancement of quantum technologies."
By the way, optical tweezers are special scientific instruments that use a highly focused laser beam to trap or move microscopic objects – even a single molecule or nanoparticle!
What excites the new PhD most is his successful creation of certain light beams – so-called skyrmions and bimerons – which have a structure resembling that of particles. He also described Airy and Bessel-type light beams.
Furthermore, by employing Lorenz-Mie theory, Justas analysed the interaction between optical vortices (light beams in which light appears to "spiral" like a helix or corkscrew) and nanoparticles.
Info: FTMC