| 1. |
- Ivanov, Konstantin A., et al.
(författare)
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Control of the surface plasmon dispersion and Purcell effect at the metamaterial-dielectric interface
- 2020
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Ingår i: Scientific Reports. - : NATURE RESEARCH. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- The use of metamaterial as a way to mitigate the negative effects of absorption in metals on the Purcell effect in metal-dielectric structures is investigated. A layered metal-dielectric structure is considered as an anisotropic medium in the long-wavelength limit. The dispersion of the surface plasmon appearing at the boundary between such a structure and a different dielectric material, as well as the position of the peak in the local density of states are studied for various combinations of materials and filling factors of the periodic structure. The calculated frequency dependence of the Purcell factor demonstrates an increase in peak value compared to the conventional plasmonic structure. The results obtained using effective media approach are compared to the results of numerical modelling.
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| 2. |
- Pozina, Galia, et al.
(författare)
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Approach to high quality GaN lateral nanowires and planar cavities fabricated by focused ion beam and metal-organic vapor phase epitaxy
- 2018
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a method to fabricate GaN planar nanowires and cavities by combination of Focused Ion Beam (FIB) patterning of the substrate followed by Metal Organic Vapor Phase Epitaxy (MOVPE). The method includes depositing a silicon nitride mask on a sapphire substrate, etching of the trenches in the mask by FIB with a diameter of 40 nm with subsequent MOVPE growth of GaN within trenches. It was observed that the growth rate of GaN is substantially increased due to enhanced bulk diffusion of the growth precursor therefore the model for analysis of the growth rate was developed. The GaN strips fabricated by this method demonstrate effective luminescence properties. The structures demonstrate enhancement of spontaneous emission via formation of Fabry-Perot modes.
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| 3. |
- Pozina, Galia, et al.
(författare)
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Nonlinear behavior of the emission in the periodic structure of InAs monolayers embedded in a GaAs matrix
- 2017
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Ingår i: Physica status solidi. B, Basic research. - : WILEY-V C H VERLAG GMBH. - 0370-1972 .- 1521-3951. ; 254:4
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Tidskriftsartikel (refereegranskat)abstract
- We report time-resolved photoluminescence (TRPL) measurements performed at different temperatures for the Bragg structure containing 60 InAs monolayer-based quantum wells (QWs) periodically arranged in a GaAs matrix. TRPL data reveal an appearance of the additional superradiant (SR) mode originated from coherent collective interaction of QWs. The SR mode is not manifested in the case if a small number of QWs is excited, then only an exciton emission related to the InAs QWs dominates the PL spectrum. The SR mode demonstrates a superlinear dependence of the intensity and radiative decay rate on the excitation power and its intensity increases at elevated temperatures compared to the excitonic emission. The photoluminescence delay time is much shorter for the SR mode indicating that the relaxation of hot excitons can occur via stimulated scattering processes. The specific behavior of the SR emission can have a strong potential for different applications such as optical logic devices, superluminescent diodes, optical switches, and low-threshold lasers. Time-resolved photoluminescence image at low temperature for the Bragg structure consisting of InAs monolayer-based quantum wells (inset).
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