Controllable A-T Splitting and Spatial Splitting Inside a Cascade Three-Level Atomic System

We illustrate the experimental observations of Autler-Townes splitting and the spatial splitting in an electromagnetically induced transparency window in a atomic vapor system of D1 line. As the power of the dressing laser beam changes, we study first-order and secondary Autler-Townes splitting. The influences of these dressing beams, which lead to the larger spatial splitting of four-wave mixing and the shift of probe transmission signal with by changing frequency detuning. Studies on such controllable Autler-Townes splitting and spatial splitting effect can be very useful in applications of spatial signal processing and optical communication.

Microwave Complex-Ratio-Measuring Circuits

This chapter reviews the microwave complex ratio measuring (MCRM) circuits which are used for complex reflection coefficient measurement. This MCRM circuit is relatively simple and cost-effective. There are various structures for the MCRM circuit, such as multi-probe transmission line circuits, five-port ring circuits, six-port hybrid coupler-based circuits, switched-reflector circuits, dual-generator circuits, and Wheatstone bridge-based circuits. Each structure of the circuits has its own advantages and disadvantages. In this chapter, the MCRM circuit calibration process has been described in detail.

ANALYSIS OF MULTI-PROBE MEASURING LINE MODEL AND CALCULATION OF UNCERTAINTY OF MEASUREMENT WITH ITS HELP

The article considers the uncertainty method and its use in modern measuring systems in microwaves. The advantages of the method are described, they demonstrate the effectiveness of the uncertainty method in estimating errors that occur during operation and calibration of a multi-probe transmission line reflectometer (MTLR) which can be used as a receiver in software-defined radio communication systems. The equations are obtained for the measurement uncertainties of MTLR due to various sources: errors in measuring voltages at the outputs of detectors, errors in calibration, inaccuracies in the knowledge of the wavelength in the line, and distances from the test load to the sensors. To analyze the uncertainties of types A and B, a numerical simulation of measuring the estimated parameters was carried out. Based on the data obtained, the results show that the expressions for dispersion matrices fully describe the nature of the measurement uncertainty in the ranges of variances of different error sources. The results of computer simulation confirming the theoretical conclusions are presented.

Transmission of Moroccan watermelon mosaic virus (MWMV) by Aphids in Greece

The aphid-transmitted Moroccan watermelon mosaic virus (MWMV; Potyvirus, Potyviridae) is an emerging pathogen in cucurbit crops in the Mediterranean basin but information on its transmitting vector species is limited. This study aimed to record the competence of 22 species of the Greek aphid fauna to vector MWMV. Timed-probe transmission experiments and arena tests were performed using laboratory colonies of aphid species abundant in field surveys; less common species were tested as apterous individuals collected directly from field plants in mass-inoculation (nonpersistent) tests. Depending on the test, aphids were tested in cohorts of 10 or 20 individuals on zucchini (Cucurbita pepo L.) plants and the frequency of transmission was calculated for a single aphid. Among 12 species tested in timed-probe transmission tests, Myzus persicae nicotianae (74.0%) appeared to be the most efficient vector, followed by M. persicae (48.0%), Aphis gossypii (11.8%), an unidentified Aphis sp. (11.8%), and A. spiraecola (11.0%). Alatae of nine species tested in arena tests transmitted the virus in rates varying from 0.7 to 53.6%; M. persicae was the most efficient species in virus spread. In mass-inoculation tests, the probability that apterae of 12 aphid species collected from field plants transmitted MWMV fluctuated from 0.3 to 5.3%. No transmission was obtained by Brevicoryne brassicae. The following species are reported as new vectors of MWMV: A. fabae, A. nerii, A. spiraephaga, A. umbrella, Capitophorus eleaegni, Dysaphis (Pomaphis) pyri, Macrosiphoniella sanborni, Macrosiphum rosae, Myzocallis castanicola, Myzus persicae nicotianae, M. cerasi, M. varians, Phorodon humuli, Ovatus crataegarius, Takecallis arundicolens (first report in Greece), Uroleucon sonchi, and U. (Uromelan) aeneum. These results contribute to a better understanding of MWMV epidemiology.

Tunneling Control of Transmission Coefficient and Group Index in a Quantum Dot Nanostructure

We theoretically study the transmission and group index properties of the probe field in a four-level quantum dot molecule. It is found that the tunnel coupling plays a very important role in realizing the transmission coefficient of the probe field. Moreover, the impact of an incoherent pump field on imaginary part of susceptibility is investigated. We show that probe transmission exhibits oppositional behavior against weak and strong incoherent pump rates. This approach allows substantial flexibility in the manipulation of group velocity of light.