Optical vector network analysis of ultra-narrow transitions in 166^{166}Er3+^{3+}:7^7LiYF4_4

We present optical vector network analysis (OVNA) of an isotopically purified $^{166}$Er$^{3+}$:$^7$LiYF$_4$ crystal. The OVNA method is based on generation and detection of modulated optical sideband by using a radio-frequency vector network analyzer. This technique is widely used in the field of microwave photonics for the characterization of optical responses of optical devices such as filters and high-Q resonators. However, dense solid-state atomic ensembles induce a large phase shift on one of the optical sidebands which results in the appearance of extra features on the measured transmission response. We present a simple theoretical model which accurately describes the observed spectra and helps to reconstruct the absorption profile of a solid-state atomic ensemble as well as corresponding change of the refractive index in the vicinity of atomic resonances.Comment: 4 pages, 5 figure

All-Optical Control of the Silicon-Vacancy Spin in Diamond at Millikelvin Temperatures.

The silicon-vacancy center in diamond offers attractive opportunities in quantum photonics due to its favorable optical properties and optically addressable electronic spin. Here, we combine both to achieve all-optical coherent control of its spin states. We utilize this method to explore spin dephasing effects in an impurity-rich sample beyond the limit of phonon-induced decoherence: Employing Ramsey and Hahn-echo techniques at temperatures down to 40 mK we identify resonant coupling to a substitutional nitrogen spin bath as limiting decoherence source for the electron spin.This research has been partially funded by the European Community’s Seventh Framework Programme (FP7/2007-2013) under Grant agreement No. 611143 (DIADEMS). M. A. gratefully acknowledges financial support by the European Research Council ERC Consolidator Grant Agreement No. 617985 and the EPSRC National Quantum Technologies Programme NQIT EP/M013243/1. B. P. thanks Wolfson College (University of Cambridge) for financial support. P. B. gratefully acknowledges financial support by the Deutsche Forschungsgemeinschaft (Grants No. BU2510/2-1, No. INST256/415-1)

OVNA-measured coherence in erbium doped Y<inf>2</inf>SiO<inf>5</inf> and LiYF<inf>4</inf> crystals at sub-Kelvin temperatures

© 2020 Author(s). The optical vector network analysis technique is a handful technique in analysis of optical networks. We here discuss application of the optical vector network analysis for the coherence studies in atomic ensembles

Electromagnetically induced transparency in a mono-isotopic ¹⁶⁷Er:⁷LiYF<inf>4</inf>crystal below 1 Kelvin: Microwave photonics approach

© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement. Electromagnetically induced transparency allows for the controllable change of absorption properties, which can be exploited in a number of applications including optical quantum memory. In this paper, we present a study of the electromagnetically induced transparency in a 167Er:7LiYF4 crystal at low magnetic fields and ultra-low temperatures. The experimental measurement scheme employs an optical vector network analysis that provides high precision measurement of amplitude, phase and group delay and paves the way towards full on-chip integration of optical quantum memory setups. We found that sub-Kelvin temperatures are the necessary requirement for observing electromagnetically induced transparency in this crystal at low fields. A good agreement between theory and experiment is achieved by taking into account the phonon bottleneck effect

ВЕГЕТАТИВНАЯ ПРОДУКТИВНОСТЬ РАСТЕНИЙ МАЛИНЫ (RUBUS IDAEUS L.) ПОСЛЕ КУЛЬТИВИРОВАНИЯ IN VITRO

The vegetative productivity of raspberry varieties Alyonushka and Meteor after in vitro propagation is evaluated, and the productivity of raspberry plants grown in different regions of Belarus is compared. It’s established that vegetative productivity of raspberry plants after in vitro depends on a variety, plants age, and the region of growing. The largest amount of young plants per one mother plant of Alyonushka variety was obtained after the first year of plant growing, and Meteor variety – after the third year. It’s shown that the vegetative productivity of Alyonushka variety is higher when it’s grown in Gomel region.Проведена оценка вегетативной продуктивности растений малины сортов Аленушка и Метеор в полевых условиях после культуры in vitro, а также сравнение продуктивности оздоровленных маточников при выращивании в разных областях Беларуси. Установлено, что вегетативная продуктивность растений малины после культуры in vitro зависит от сорта, возраста растений, а также региона возделывания маточника. Наибольшее количество саженцев с одного маточного куста у растений сорта Аленушка было получено в 1-й год эксплуатации маточника, а для растений сорта Метеор – на 3-й год. Показано, что вегетативная продуктивность растений сорта Аленушка была выше при выращивании растений в условиях Гомельской области.Ил. 1. Табл. 1. Библиогр. – 7 назв

Influence of Defects Introduced by Irradiation with 4-9 MeV Helium Ions on Impedance of Silicon Diodes

Silicon diodes irradiated with helium ions with energies of 4.1, 6.8 and 8.9 MeV are studied. It is shown that the mechanism determining the behaviour of frequency dependence of complex electric module and correspondingly the behavior of impedance of diodes irradiated with helium ions in the frequency region 3-200 kHz is a recharging of vacancy complexes localized in the space charge region

Testing of Generalized Uncertainty Principle With Macroscopic Mechanical Oscillators and Pendulums

International audienceRecent progress in observing and manipulating mechanical oscillators at quantum regime provides new opportunities of studying fundamental physics, for example to search for low energy signatures of quantum gravity. For example, it was recently proposed that such devices can be used to test quantum gravity effects, by detecting the change in the [^x,^p] commutation relation that could result from quantum gravity corrections. We show that such a correction results in a dependence of a resonant frequency of a mechanical oscillator on its amplitude, which is known as the amplitude-frequency effect. By implementing this new method we measure the amplitude-frequency effect for a 0.3 kg ultra-high-Q sapphire split-bar mechanical resonator and for an ∼10−5  kg quartz bulk acoustic wave resonator. Our experiments with a sapphire resonator have established the upper limit on a quantum gravity correction constant of β0 to not exceed 5.2×106, which is a factor of 6 better than previously measured. The reasonable estimates of β0 from experiments with quartz resonators yields β0<4×104. The datasets of 1936 measurements of a physical pendulum period by Atkinson [E. C. Atkinson, Proc. Phys. Soc. London 48, 606 (1936).] could potentially lead to significantly stronger limitations on β0≪1. Yet, due to the lack of proper pendulum frequency stability measurement in these experiments the exact upper bound on β0 cannot be reliably established. Moreover, pendulum based systems only allow one to test a specific form of the modified commutator that depends on the mean value of momentum. The electromechanical oscillators to the contrary enable testing of any form of generalized uncertainty principle directly due to a much higher stability and a higher degree of control

МИКРОРАЗМНОЖЕНИЕ СОРТОВ ХМЕЛЯ IN VITRO

The basis for the establishment of virus-free hop plant production has been created for the first time in Belarus. Regeneration of apical meristems and vegetative buds of hop in vitro has been studied. Biological and technological elements (culture medium composition at different stages of propagation in vitro, types of explants and variety peculiarity) have been developed.Впервые в условиях Беларуси создана основа для создания собственного производства оздоровленного посадочного материала хмеля (Humulus Lupulus L.), в том числе изучена регенерационная способность апикальных меристем и вегетативных почек хмеля в условиях in vitro; разработаны биологические и технологические составляющие получения посадочного материала хмеля в культуре in vitro (состав питательных сред на различных этапах размножения in vitro, типы эксплантов, сортоспецифичность).Ил. 3. Табл. 5. Библиогр. – 11 назв