The KAU Department of Fundamental Problems of General and Applied Physics is based at the Institute of Physics of the NAS of Ukraine.

The Department offers the Bachelor’s, Master’s and PhD education programs in modern areas of quantum and nonlinear optics, laser physics. The main areas of research are:

1. Physics of Lasers and Laser Materials;

2. Nonlinear and Singular Optics;

3. Fundamental Research of the Interaction of Laser Radiation with Matter and the Development of Scientific Base of Laser Technologies;

4. Holography.

During the studies, students are involved in research in the physics of gas, solid-state lasers and dye lasers. They study nonlinear optical phenomena in semiconductor, molecular and liquid crystals, photorefractive materials, polymers, organic molecules, photopolymer materials for holography and information recording. Moreover, students work on nonlinear ultrahigh-resolution laser spectroscopy and develop new methods for laser control of the motion of free atomic particles. Along with the traditional areas for the Institute, such as dynamic holography and multi-beam optics, speckle-field physics and holographic correlation methods for laser beam transformation, new ones areas are also being studied - for example, singular laser beam optics.

### Possible supervisors and topics of Master's theses:

**Morozovska Anna Mykolaivna, **Doctor of Physical and Mathematical Sciences, Leading Researcher at the Institute of Physics of the National Academy of Sciences of Ukraine, Department of Magnetic Phenomena Physics (Theoretical physics, h factor = 48 according to Google Scholar, h factor = 39 according to Scopus, > 6900 citations), This email address is being protected from spambots. You need JavaScript enabled to view it., http://www.iop.kiev.ua/en/morozovska-g-m/

**Topics of Master's theses:** influence of dimensional effects, particle surfaces and boundaries, topological defects (dislocations, grain boundaries, magnetic and ferroelectric domain walls) on the structure and local dynamics of nanomaterials, in particular ferroelectrics and multiferroics.

These fundamental problems are important for a wide range of nanomaterials and the improvement of random access memory elements, piezoelectric actuators, pyroelectric detectors and electro-optical devices.

**Master's students will be able to study the following disciplines and physics phenomena:**

- phenomenological theory of ferroics (ferroelectrics, ferroelastic materials, ferromagnets);
- dimensional effects in nanomaterials (ferroelectrics and multiferroics);
- calculations of the influence of surface and dimensional effects on the functional properties of ferroics;
- domain structure of ferroics;
- dynamics of polarization reversal in nanoscale regions;
- the effect of symmetry breaking near the surface or interface, defects, inhomogeneous voltages and dimensional effects on the structure of the domain wall;
- study of unordinary ferroelectric nanostructures;
- graphene-ferroelectric;
- flexoelectric phenomena in meso- and nanomaterials; their influence on phonon spectra and spatially modulated phases;
- semiconductors with a mixed type of conductivity, superionics, ferronics.

**Masters are going to such methods of theoretical research** as the Landau-Ginzburg-Devonshire phenomenological theory of phase transitions, classical electrodynamics and thermodynamics, statistical physics, various methods of mathematical physics, numerical simulation in COMSOL and MathLab.

**They will learn such modern methods of experimental research** as scanning probe microscopy, in particular piezoelectric force microscopy, studies of the dynamics of polarization reversal on a nanoscale, electrochemical microscopy of deformations.

**Joint projects provide for mutual exchange and internships for students.**

**Collaboration with experimenters and theorists: **

- Department of Prof. Venkatraman Gopalan, and a group of Prof. Long-Qing Chen, Department of Materials Science and Engineering, Pennsylvania State University, USA;
- The Center for Nanophase Materials Sciences and Materials Science and Technology Division, Oak Ridge National Laboratory, USA, a group of Prof. S.V. Kalinin;
- Institut für Materialwissenschaft, Technische Universität Darmstadt, Germany, a group of Prof. Yuri A. Genenko.

**Weinberg Victor Volodymyrovych**, Doctor of Physical and Mathematical Sciences, Leading Researcher at the Department of Solid-State Electronics of the Institute of Physics of the National Academy of Sciences of Ukraine, This email address is being protected from spambots. You need JavaScript enabled to view it.

**Topic of Master’s theses:** “Electrical conductivity in heterostructures with tunnel-connected quantum wells in strong electric and magnetic fields”.

**Abstract: **Heterostructures with tunnel-connected quantum wells are a new object, promising for the creation of modern electronic and optoelectronic devices. New ideas of such devices are offered in scientific periodicals, in particular, for mastering the current terahertz spectral range of electromagnetic waves, both for generation and detection, microwave generators, etc. Such heterostructures provide opportunities to control the spectrum of electronic states and related electrical properties. This requires to study their galvanomagnetic properties in a wide range of temperatures, electric and magnetic fields. When working on a master's thesis, the student is expected to master experimental research techniques using cryogenic liquids, strong electric and magnetic fields, mastering the method of making samples for research, and electrical contacts. The theoretical part includes the study of the physical basis of galvanomagnetic phenomena that determine the electrical conductivity of the studied structures, including, in particular, the Hall effect (including the quantum Hall effect), quantum corrections to conductivity, and magnetoresistance. At the same time, methods for calculating the energy spectrum of electronic states, conductivity, etc. in such complex objects (including numerical methods using computer programs).

** Links to publications**VVVainberg ,OGSarbey,AS Pylypchuk,VNPoroshin andNVBaidus. A peculiarity of quantum hot-electron real space transfer in dual-channel GaAs-based heterostructures. J. Phys. Commun. 1 (2017) 045002 https://doi.org/10.1088/2399-6528/aa90c9

V.V. Vainberg, A.S. Pylypchuk, V.N. Poroshin, O.G. Sarbey,N.V. Baidus, A.A. Biryukov. Influence of conduction via a channel of an impurity δ-layer on the magneto-quantum effects in AlGaAs/GaAs/AlGaAs heterostructures. Physica E 60 (2014) 31–36.

Yu. N. Gudenko, V. V. Vainberg,a) V. M. Vasetskii, V. N. Poroshin, O. G. Sarbey,and S. V. Chirchik. Negative residual infrared photoconduction in the p-SiGe/Si heterostructures with selectively doped quantum wells. J. Appl. Phys. 112, 083715 (2012); doi: 10.1063/1.4759283

**Bugaychuk Svitlana Anatoliyivna**, PhD in Physical and Mathematical Sciences, Senior Researcher at the Department of Crystal Physics of the the Institute of Physics of the National Academy of Sciences of Ukraine, This email address is being protected from spambots. You need JavaScript enabled to view it.

**Topics of Master's theses:**1) Research on extreme events in the interaction of laser beams in nonlinear dynamic environments with relaxation. (Theoretical work)

2) The effects of giant amplification of laser beams in their nonlinear interaction in dynamic environments with relaxation. (Experimental work)

**Abstract**:

One of the modern directions of nonlinear photonics is the effects of waves self-influence that occur during the interaction of coherent laser beams in a nonlinear environment. It has recently been discovered that in dynamic environments with relaxation of nonlinearity it is possible to excite dissipative longitudinal solitons. There are two master's theses, theoretical and experimental, devoted to the study of these solitons and the effects associated with them, which occur when laser pulses interact in liquid crystal valves.

One of the interesting, but little-studied phenomena associated with dissipative solitons is the generation of extreme events (high-intensity pulses) as well as giant pulses (so-called “killer waves”). Such pulses occur in nonlinear systems, but in addition to high intensities, which significantly exceed the average intensity of the output pulses, they are also characterized by so-called "long-tail statistics", i.e. the frequency of such high-intensity pulses significantly exceeds the statistics of random events. It should also be noted that extreme waves and “killer waves” are the subject of modern geophysical studies of waves in the oceans and seas. Since dissipative solitons in optics and on the water surface are described by the same nonlinear differential equations, their properties are usually researched in parallel.

Thus, the proposed master's theses are interdisciplinary, combining nonlinear optics, mathematics of dissipative solitons, mathematical statistics, nonlinear optical properties of liquid crystals, and the results of these studies can be used to predict extreme waves and “killer waves” on water.

When doing **theoretical work 1)** it is planned:

- to develop a program that calculates the occurrence of dissipative solitons in a nonlinear system of wave interaction in dynamic environment with relaxation;

- to investigate the conditions of occurrence of extreme waves and “killer waves” depending on the parameters of the system, in particular, on the correlation between the periodicity of laser pulses and the relaxation time of nonlinearity in the liquid crystal, T / t;

- perform calculations of the initial wave intensities depending on T / t, as well as statistical calculations for these intensities.

The program is planned to be created on the basis of the MatLab package; or develop an original program in C ++ or Delphy.

**Experimental Master's thesis 2)** includes the following:

- preparation of liquid crystal valves;

- development of experimental installation of two-beam interaction of laser waves in a liquid crystal valve, taking into account the application of voltage (constant, alternating) to the liquid crystal, use of chopper to generate laser pulses of different duration and frequency, use of digital oscilloscope for computer recording of output intensities;

- measurements of the output intensities of laser pulses for different correlation of the frequency of laser pulses and relaxation times of nonlinearity in different types of liquid crystals;

- statistical processing of measurement results.

The proposed works are original, according to the results of research it will be proposed to prepare publications.

** Publications of the supervisor on the topic of master's theses: **S. Bugaychuk, E. Tobisch, “Single evolution equation in a light-matter pairing system”,

*J. Phys. A: Math. Theor.*,

**51**(12), 125201 (2018).

S. Bugaychuk, A. Iljin, O. Lytvynenko, L. Tarakhan, L. Karachevtseva, “Enhanced nonlinear optical effect in hybrid liquid crystal cells based on photonic crystal”,

*Nanoscale Research Letters*,

**12**:449, 1-9 (2017).

S. Bugaychuk, A. Iljin, K. Chunikhina, “Extereme events induced by self-action of laser beams in dynamic nonlinear liquid crystal valves”,

*Journal of Physics: Conference Series*

**867**(1), 012007 (2017).

S. Bugaychuk and R. Conte, “Nonlinear amplification of coherent waves in media with soliton-type refractive index pattern”,

*Phys. Rev. E.*

**86**, 026603-1-8 (2012).

**Goncharov Oleksii Antonovych**, Prof., Doctor of Physical and Mathematical Sciences, Chief Researcher, This email address is being protected from spambots. You need JavaScript enabled to view it..

1.** Determination of the ion energy distribution in the ion-plasma flux generated by a modified Hall accelerator of the new generation.**

Determination of electrophysical and plasmodynamic characteristics of ion-plasma flux. Introduction to general methods of plasma diagnostics. Experimental determination of ion energy distribution in ion-plasma flux. Probe measurements in low-temperature plasma. Introduction to the operation of vacuum systems. Mastering the principles of operation of plasmodynamic systems of medium energies of the Hall type. Possibility to publish scientific articles and reports at conferences based on research results.

A.A. Goncharov, A.N. Dobrovolskiy, I.V. Naiko, L.V. Naiko, I.V. Litovko. Modes of Plasma-Dynamical System with Closed Electron Drift and Open Walls. DOI10.1109/YSF.2017.8126633

A.A. Goncharov, I. V. Litovko, A. N. Dobrovolsky, L. V. Najko, and I. V. Najko. Novel modification of Hall-type ion source (study and the first results). *Review of Scientific Instruments * **87**, 02A501 (2016)

2. **Research on the interaction of fast electrons with macroparticles in a dense dusty metal plasma (analytical calculations and computer modeling).**

Introduction to analytical and numerical methods of research of physical processes in dusty plasma. Participation in the creation of a physical and mathematical model that describes the energy interaction of fast electrons with macroparticles of dense metal plasma. Gaining experience in solving complex mathematical equations and establishing the dominant physical factors that determine the processes of effective destruction of macroparticles. Possibility to publish scientific articles and reports at conferences based on research results.

A.A. Goncharov. Plasma dynamical devices: review of fundamental results and applications. Apple Acad. Press 2017, chapter 2 in book “Plasma and Fusion Science” pp.17-30.