43 research outputs found
Spin polarization of exciton-polariton condensate in a photonic synthetic effective magnetic field
We investigate the spin polarization of localized exciton-polariton
condensates. We demonstrate the presence of an effective magnetic field leading
to the formation of elliptically polarized condensates. We show that this
synthetic field has an entirely photonic origin, which we believe is unique for
the CdTe-based microcavities. Moreover, the degree of spin polarization of
localized polariton condensates in samples with magnetic ions depends on the
excitation power or polarization of the non-resonant excitation laser. In an
external magnetic field, the semimagnetic condensate spontaneously builds up
strong spin polarization. Based on the magnetic field behavior of the
condensate in the presence of magnetic ions, we apply a model that allows us to
estimate the polariton-polariton interaction strength in a CdTe-system to
approx. 0.8
Electrical switching of a chiral lasing from polariton condensate in a Rashba-Dresselhaus regime
Efficient optical classical and quantum information processing imposes on
light novel requirements: chirality with low threshold non-linearities. In this
work we demonstrate a chiral lasing from an optical modes due to emerging
photonic Rashba-Dresselhaus spin-orbit coupling (SOC). For this purpose we
developed a new electrically tunable device based on an optical cavity filled
with birefringent liquid crystal (LC) and perovskite crystals. Our novel method
for the growth of single crystals of CsPbBr inorganic perovskite in polymer
templates allows us to reach a strong light-matter coupling regime between
perovskite excitons and cavity modes, and induce polariton condensation. The
sensitivity of the LC to external electric fields lets us to tune the
condensate energy in situ and induce synthetic SOC. This shapes the condensate
between a single linearly polarized or two circularly polarized separated in
momentum, emitting coherent light. The difference in the condensation
thresholds between the two SOC regimes can be used to switch on and off the
chiral condensate emission with a voltage.Comment: 8 pages, 5 figure
Angular dependence of giant Zeeman effect for semimagnetic cavity polariton
The observation of spin-related phenomena of microcavity polaritons has been limited due to the weak Zeeman effect of nonmagnetic semiconductors. We demonstrate that the incorporation of magnetic ions into quantum wells placed in a nonmagnetic microcavity results in enhanced effects of magnetic field on exciton-polaritons. We show that in such a structure the Zeeman splitting of exciton-polaritons strongly depends on the photon-exciton detuning and polariton wave vector. Our experimental data are explained by a model where the impact of magnetic field on the lower polariton state is directly inherited from the excitonic component, and the coupling strength to the cavity photon is modified by an external magnetic field
New Middle-Class Labor Migrants
Migration researchers have tended to focus on social extremes: either highly skilled elites, on the one hand, or low-wage workers on the other. Less attention has been directed toward “ordinary” middle-class professional movers, and there have been no reviews of this literature to date. The chapter addresses this gap and identifies five important themes to guide future class-orientated migration research. First, the complex relationship between migration, social mobility, place, and middle-class membership is examined. Second, age is shown to be an important consideration in middle-class migration decision-making. Third, the cultural versus economic basis of the mobile middle-class is explored, and the role of lifestyle factors in shaping migration is critically examined. Fourth, middle-class migration decisions are connected to gendered household strategies, with the preponderance of dual-career couples now taking migration decision-making well beyond the individual career path. Finally, the social and communal emplacement of middle-class migrants is considered as an important but neglected dimension of research. Overall, it is clear that the class-based analysis of migration is an important yet neglected field of study, and this is especially true for middle-class movers
Improving quality of cytological screening in early detection of malignancy associated changes
The paper deals with an image database organization and utilization in computer-aided cytology. To illustrate the idea we take as an example the problem of bladder cancer early detection based on urine cytology. In spite of its diagnostic potential for discovering malignancy associated changes (MAC) at the cell level it seems to be underestimated. There is common view that sensitivity of the method, especially for early cancer stages, is relatively low. We depict here just one but significant direction of our works that aims to support pathologists making the diagnosis more accurate and reliable. The key idea relies on automatic searching for MAC by comparing nuclear chromatin structure of objects in a smear with a collection of sample patterns contained in a pathomorphological image database