In recent years, Faculty of Physics and Mathematics carries out collaborations with Los Alamos National Laboratory (LANL). This laboratory was founded in 1943 for the Manhattan project on atomic weapon creation.
Now LANL holds fundamental researches in many branches of physics involving scientists from various countries.
A series of works, accomplished with the direct participation of professor V. Gorshkov (Faculty of Physics and Mathematics, NTUU "KPI"), resulted in publication of the book "Magnetic resonance and microscope and a single spin measurement", World Scientific, 2006. It concerns single electron spins registration methods in solid bodies and gives a unique research tool in physics, chemistry, biology and medicine.
Propagation of initially coherent laser beam in turbulent atmosphere. Example of numerical simulation that demonstrates both fragmentation and beam wandering
Productive cooperation of NTUU "KPI" and LANL in the field of laser beam optical communications (Prof. V. Gorshkov, graduate student S. Torous) is carried out. The communication of this kind is characterized by high communicability, privacy and high information density of transferred signal. A significant factor that hinders the realization of the major technical decisions is the atmosphere, which is turbulent at almost any weather conditions. Even small spatial variations of refractive index result in laser beam distortion. The beam gets fragmented (splitted into single rays) in the process of propagation and deviates from the original direction. The level of received signal becomes random. This increases errors probability in the information decoding. Researches, which are carried out at the Faculty of Physics and Mathematics, are dedicated to the development of methods for fluctuation suppression in detector signal.
Widespread use of numerical simulation in the study of the so-called partially coherent beams (including optical vortices) propagation in turbulent atmosphere allows to achieve fluctuation reduction in the signal in 20 times. This index is a world record today. The results of joint work are published in the JOURNAL OF PHYSICS B: ATOMIC, MOLECULAR AND OPTICAL PHYSICS (2009), are highly appreciated at the annual conference Photonics West-San Francisco-2009 and are included into the list of the highest achievements of LANL in 2009.
One of the random phase distributions of the Phase Modulator (only the interval is shown); b - The correlation function of the PM
a - Comparison of scintillation indices of coherent Gaussian beam (curves 1, 2) and optical vortex (curves 1 ', 2'). In both cases, averaging is held over 2500 atmosphere states. b - the probability distribution function for optical vortex.
Cooperation agreement on for the next three years is at the stage of ratification now.
Memorandum of Understanding Between Los Alamos National Laboratory and National Technical University of Ukraine "KPI".
The implementation of collaboration is supposed in the following fields:
· Theory and modeling of propagation of light through the turbulent atmosphere;
· Theory and modeling of sensors and imagers;
· Modeling the dynamics of quantum systems interacting with the environment;
· Modeling of electromagnetic radiation scattering and absorption by NSS;
· Study of surface-enhanced Raman scattering (SERS) and fluorescence of molecules adsorbed on the NSS interfaces and on micro-resonators;
· Modeling of controlled growth of nano-particles.
The house where the neutrino discoverer D. Chadwick and the “father” of plutonium chemistry Richard Baker have lived (Los Alamos, USA).
Centre for Advance Material Processing, (Clarkson University, NY)
During the last three years active collaboration under corresponding agreement with the Centre for Advance Material Processing, (Clarkson University, NY) is carried out.
Research works are dedicated to the physics of nanosystems. It is known that the properties of the same substance confined within the particle of 100-200nm sizes are significantly different from the physical and chemical properties of micrometer scale (and above) particles. Nanoparticles find the widest application in medicine, microelectronics, and even in agriculture. Methods of nanoparticles synthesis should provide their monodispersity (uniformity in size) and possibility to control form, which influences significantly on physical and chemical properties of particles. Often particle shape varies for the same initial substances depending on the formation regime.
Iron nanoparticles forms obtained in the work - Wang, CM, DR Baer, JE Amonette, MH Engelhard, Y Qiang, and J Antony. 2007. "Morphology and oxide shell structure of iron nanoparticles grown by sputter-gas-aggregation." Nanotechnology 18:255603
Research work of NTUU "KPI" and Clarkson University physicists is dedicated to the theory of nanoparticles form control during their growth. It is shown that the regular polyhedron nanoparticle forms are often the result of substantially nonequilibrium diffusion growth regimes, which can be controlled by changing system temperature and free atoms (molecules) concentration.
Theoretical recommendations are confirmed by real experiments. Below are abstracts from one of the recent publication (2009). Numerical simulation is accomplished by the unique algorithm (V. Gorshkov, A. Zavalov), which allows to describe quite accurately the dynamics of systems including several millions of free atoms (molecules) and the dynamics of surface atoms (molecules) of growing nanoparticles.
Regularities in the nanoparticle formation mechanisms have attracted considerable interest among the specialists, and the article itself has become the subject of attention at many sites, starting from the site of NASA space agency and finishing with medical sites.
Also, the international scientific collaboration is carried out with the following universities:
- Rome University (Faculty of Mathematics)
- University of Salermo (Faculty of Informatics and Mathematics)
- University of Naples (Faculty of Engineering)
- University of Bologna (Faculty of Mathematics)
- University of Toronto
- University of Lisbon
- University of Barcelona
- University of New York