Surface acoustic wave modulation of single photon emission from GaN/InGaN nanowire quantum dots

On-chip quantum information processing requires controllable quantum light sources that can be operated on-demand at high-speeds and with the possibility of in-situ control of the photon emission wavelength and its optical polarization properties. Here, we report on the dynamic control of the optical emission from core-shell GaN/InGaN nanowire (NW) heterostructures using radio frequency surface acoustic waves (SAWs). The SAWs are excited on the surface of a piezoelectric lithium niobate crystal equipped with a SAW delay line onto which the NWs were mechanically transferred. Luminescent quantum dot (QD)-like exciton localization centers induced by compositional fluctuations within the InGaN nanoshell were identified using stroboscopic micro-photoluminescence (micro-PL) spectroscopy. They exhibit narrow and almost fully linearly polarized emission lines in the micro-PL spectra and a pronounced anti-bunching signature of single photon emission in the photon correlation experiments. When the nanowire is perturbed by the propagating SAW, the embedded QD is periodically strained and its excitonic transitions are modulated by the acousto-mechanical coupling, giving rise to a spectral fine-tuning within a ~1.5 meV bandwidth at the acoustic frequency of ~330 MHz. This outcome can be further combined with spectral detection filtering for temporal control of the emitted photons. The effect of the SAW piezoelectric field on the QD charge population and on the optical polarization degree is also observed. The advantage of the acousto-optoelectric over other control schemes is that it allows in-situ manipulation of the optical emission properties over a wide frequency range (up to GHz frequencies).Comment: arXiv admin note: text overlap with arXiv:1902.0791

Diversification of transit risks of Russia as a basis for economic and energy security in European countries

The paper examines the dependence of energy security against the European Union (EU) and Russia, where the main threats are the insufficient diversification of supplies, the difficulties in gas transportation and the high transit tariffs. It covers the threats of location of the gas transportation system in Ukraine, through the territory of which a significant volume of gas purchases to the EU countries is delivered. The ways of diversifying transit risks have been identified through the Yamal-Europe, Blue Stream, and Nord Stream gas pipelines, as well as by the implementation of the Nord Stream 2 gas pipeline. This will allow diversifying the EU transit risks and supplying gas to Austria through the territory of Germany, the Czech Republic and Slovakia. In turn could be determined by political and economic instability. In the methodological part of the paper, an analysis of gas consumption in the countries of Central and Eastern Europe was made, which showed fairly stable consumption with a slight decrease in demand.peer-reviewe

Religious and secular basics in preaching of Patriarch Kirill

The article considers religious and secular speech-behavioral tactics to condemn sin (anger, envy, blame, lies, wealth) in preaching of Holy Patriarch Kirill. The kinds of speech-behavioral tactics to condemn every sin in general language use and their speech realizations are identified. Religious and secular speech-behavioral tactics preferred by Patriarch Kirill in accordance with spiritual-moral image of Russian society in early 2000s are described. © IDOSI Publications, 2014

Software selection based on analysis and forecasting methods, practised in 1C

The research focuses on the problem of a "1C: Enterprise 8" platform inboard mechanisms for data analysis and forecasting. It is important to evaluate and select proper software to develop effective strategies for customer relationship management in terms of sales, as well as implementation and further maintenance of software. Research data allows creating new forecast models to schedule further software distribution