Jobs - Topics of PhD study

Super-resolution in holographic incoherent-light-source quantitative phase imaging using classical or quantum approaches  

Holographic incoherent-light-source quantitative phase imaging (HiQPI) is a unique imaging technique developed by our group. It allows obtaining high-quality quantitative phase images of samples, such as living cells, even when they are immersed in a scattering environment. A big challenge for quantitative phase imaging is to achieve super-resolution, as the usual approaches in microscopy are not applicable. Recent calculations, simulations and experiments have shown that in HiQPI it is possible to achieve sub-diffraction resolution (super-resolution) due to partially coherent illumination, which is unique in holographic microscopy. The area of application of quantum Fisher information, allowing to break the classical resolution limit in the case of special types of objects, also remains unexplored. The student will explore various techniques to achieve super-resolution and their utility in HiQPI. Part of the solution to the topic will be a theoretical analysis of each method, a proposal for its implementation in HiQPI and, last but not least, experimental verification on a Q-Phase microscope. The most successful super-resolution technique will then be applied to an experiment with living cells.

Supervisorprof. RNDr. Chmelík Radim, Ph.D.

Imaging with geometric-phase optical elements

Geometric-phase optical elements are a new tool for complex light shaping and generation of special states of light. Unlike traditional refractive elements, the geometric-phase elements control the light using transformation of its polarization state. Thanks to technology of liquid crystals or principles of plasmonics, geometric-phase elements provide abrupt phase changes on physically thin substrates. Compact size and unique polarization properties make them ideal candidates for simply integrable spatial light modulators. The dissertation thesis topic is to find and verify the potential of geometric-phase elements in common-path digital holography and advanced optical imaging.

SupervisorIng. Petr Bouchal, Ph.D. 

Live tumor cell analysis using holographic incoherent-light-source quantitative phase imaging

The topic aims at optimizing quantitative analysis of cell behavior with high accuracy for measurements of cell reactions to experimental treatments with applications in cancer research. The topic involves cell culture, specimen preparation for microscopy, time-lapse acquisition, image processing, data analysis, and interpretation. Requirements: knowledge of fundamentals of optics, cell biology, microscopy, coding, the ability to work independently and in a team, and high motivation.

SupervisorIng. Daniel Zicha, CSc.

Artificial intelligence in advanced processing for holographic incoherent-light-source quantitative phase imaging

Address accurate reconstruction of image background and cell segmentation using artificial intelligence. Quantitative phase imaging has specific requirements, and standard approaches developed for fluorescence or other light microscopy contrast techniques are not directly applicable. Artificial intelligence will be useful in decomposing the image, and corrected raw data will be finally used to ensure maximum accuracy of the phase measurements.

SupervisorIng. Daniel Zicha, CSc.

Eigenmode expansion techniques for simulation of nanophotonic structures

The theoretical analysis of novel optical effects and functionalities in modern nanophotonic structures is impossible without adequate and powerful numerical tools. Interestingly, the methods based on eigenmode expansion (EME), enabling a deep physical understanding of the problem, are often overlooked. That is why the project will focus on development and application of EME techniques suitable for the study of selected interesting problems of contemporary nanophotonics. Application will address topics such as nanophotonic lattices that support bound states in the continuum, the issues related with the loss compensation in plasmonic structures, systems with gain and loss where realistic models of gain media based on the rate equations for the populations is used, and modulation in hybrid waveguides with graphene.

Supervisor: prof. RNDr. Jiří Petráček, Dr.

Photonic waveguide structures with BICs

Bound states in the continuum (BICs) represent a theoretically interesting way of field localization, which contradicts the conventional wisdom of bound states with energies solely outside the continuum of free states. BICs offer a number of interesting applications; for example, in photonics, BICs enable development of sensitive nanostructures with significant reduction of radiation leakage [1,2]. The project will focus on theoretical analysis and physical understanding of the operation of photonic waveguide structures supporting the propagation of a selected type of BIC. We assume the design and subsequent systematic research of selected photonic waveguide structures that resemble a lattice investigated in Ref. 3 and support the so-called symmetry protected BIC. The student will perform simulations with the aim to confirm the existence of the assumed BICs. Subsequently, the behavior of BICs will be investigated, and structural parameters will be optimized in order to achieve the required properties.
[1] K. Koshelev, A. Bogdanov, and Y. Kivshar, “Engineering with Bound States in the Continuum,” Opt. Photonics News, vol. 31, no. 1, p. 38, 2020
[2] S. I. Azzam and A. V. Kildishev, “Photonic Bound States in the Continuum: From Basics to Applications,” Adv. Opt. Mater., vol. 9, no. 1, pp. 16–24, 2021
[3] Y. Plotnik et al., “Experimental observation of optical bound states in the continuum,” Phys. Rev. Lett., vol. 107, no. 18, pp. 28–31, 2011

Supervisorprof. RNDr. Jiří Petráček, Dr.

Rigorous simulation of electromagnetic wave propagation in inhomogeneous media 

The topic is focused on development of numerical methods for rigorous simulation of electromagnetic wave propagation in arbitrary inhomogeneous media. Namely, we assume investigation of the techniques based on the expansion into plane waves and/or eigenmodes in combination with perturbation techniques. Developed techniques will applied to modeling of light scattering by selected biological samples.
- knowledge in fields of electrodynamics and optics corresponding to undergraduate courses
- basic ability to write computer code, preferably in Matlab.

Supervisor: prof. RNDr. Jiří Petráček, Dr.