A hemispherical, high-solid-angle optical micro-cavity for cavity-QED studies

We report a novel hemispherical micro-cavity that is comprised of a planar integrated semiconductor distributed Bragg reflector (DBR) mirror, and an external, concave micro-mirror having a radius of curvature $50\mathrm{\mu m}$. The integrated DBR mirror containing quantum dots (QD), is designed to locate the QDs at an antinode of the field in order to maximize the interaction between the QD and the cavity. The concave micro-mirror, with high-reflectivity over a large solid-angle, creates a diffraction-limited (sub-micron) mode-waist at the planar mirror, leading to a large coupling constant between cavity mode and QD. The half-monolithic design gives more spatial and spectral tuning abilities, relatively to fully monolithic structures. This unique micro-cavity design will potentially enable us to both reach the cavity quantum electrodynamics (QED) strong coupling regime and realize the deterministic generation of single photons on demand.Comment: 15 pages, 17 figures, final versio

Development and Validation of Social Motivation Questionnaire

Background and Objectives: Information-seeking (IS) and emotion-regulatory (ER) motivation play meaningful roles in age-related changes in social interaction across adulthood. This study aimed to develop and validate the Social Motivation Questionnaire (SMQ) to assess these two types of motivation. Research Design and Methods: Ten items were selected from a pool as the candidate items of SMQ and were administered to 480 German adults (20–91 years old) for validation. These items were also administered to 150 U.S. (18–40 years old) and 131 Hong Kong younger adults (18 to 26 years old) for cultural-invariance examination. Results: Exploratory and confirmatory factor analyses showed that a two-factor, eight-item structure fits the German adults’ data well with satisfactory reliability. Multigroup comparisons showed cross-age invariance among younger, middle-aged, and older German adults, as well as cross-cultural invariance among German, U.S., and Hong Kong younger adults. Discussion and Implications: A new questionnaire, SMQ, was developed and validated to measure IS and ER social motivation across adulthood and across cultures

Gender Stereotypes of Personality Universal and Accurate?

Numerous studies have documented subtle but consistent sex differences in self-reports and observer-ratings of five-factor personality traits, and such effects were found to show well-defined developmental trajectories and remarkable similarity across nations. In contrast, very little is known about perceived gender differences in five-factor traits in spite of their potential implications for gender biases at the interpersonal and societal level. In particular, it is not clear how perceived gender differences in five-factor personality vary across age groups and national contexts and to what extent they accurately reflect assessed sex differences in personality. To address these questions, we analyzed responses from 3,323 individuals across 26 nations (mean age = 22.3 years, 31% male) who were asked to rate the five-factor personality traits of typical men or women in three age groups (adolescent, adult, and older adult) in their respective nations. Raters perceived women as slightly higher in openness, agreeableness, and conscientiousness as well as some aspects of extraversion and neuroticism. Perceived gender differences were fairly consistent across nations and target age groups and mapped closely onto assessed sex differences in self- and observer-rated personality. Associations between the average size of perceived gender differences and national variations in sociodemographic characteristics, value systems, or gender equality did not reach statistical significance. Findings contribute to our understanding of the underlying mechanisms of gender stereotypes of personality and suggest that perceptions of actual sex differences may play a more important role than culturally based gender roles and socialization processes.Peer-reviewed manuscript: [http://reff.f.bg.ac.rs/handle/123456789/3399

Challenges in the design of concentrator photovoltaic (CPV) modules to achieve highest efficiencies

Concentrator photovoltaics (CPV) is a special high efficiency system technology in the world of PV-technologies. The idea of CPV is to use optical light concentrators to increase the incident power on solar cells. The solar cell area is comparatively tiny, thus saving expensive semiconductor materials and allowing the use of more sophisticated and more costly multi-junction solar cells. The highest CPV module efficiency achieved is 38.9%. This CPV module uses four-junction III-Vbased solar cells. Moreover, mini-modules have already achieved an efficiency of 43.4%. The interaction between optics, cells, and layout of the module and tracker determines the overall field performance. Today, some utility scale CPV plants are installed. The CPV technology allows for many technical solutions for system designs and for optimizing performance while maintaining the economics. This paper will review the achievements and discuss the challenges for the CPV module technology and its components. We discuss the different components and the most important effects regarding the module design. Furthermore, we present the module designs that have shown the highest efficiencies