781 research outputs found

    Electromechanical wavelength tuning of double-membrane photonic crystal cavities

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    We present a method for tuning the resonant wavelength of photonic crystal cavities (PCCs) around 1.55 um. Large tuning of the PCC mode is enabled by electromechanically controlling the separation between two parallel InGaAsP membranes. A fabrication method to avoid sticking between the membranes is discussed. Reversible red/blue shifting of the symmetric/anti-symmetric modes has been observed, which provides clear evidence of the electromechanical tuning, and a maximum shift of 10 nm with < 6 V applied bias has been obtained.Comment: 9 pages, 3 figure

    An AC electric trap for ground-state molecules

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    We here report on the realization of an electrodynamic trap, capable of trapping neutral atoms and molecules in both low-field and high-field seeking states. Confinement in three dimensions is achieved by switching between two electric field configurations that have a saddle-point at the center of the trap, i.e., by alternating a focusing and a defocusing force in each direction. AC trapping of 15ND3 molecules is experimentally demonstrated, and the stability of the trap is studied as a function of the switching frequency. A 1 mK sample of 15ND3 molecules in the high-field seeking component of the |J,K>=|1,1> level, the ground-state of para-ammonia, is trapped in a volume of about 1 mm^3

    Size dependent exciton g-factor in self-assembled InAs/InP quantum dots

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    We have studied the size dependence of the exciton g-factor in self-assembled InAs/InP quantum dots. Photoluminescence measurements on a large ensemble of these dots indicate a multimodal height distribution. Cross-sectional Scanning Tunneling Microscopy measurements have been performed and support the interpretation of the macro photoluminescence spectra. More than 160 individual quantum dots have systematically been investigated by analyzing single dot magneto-luminescence between 1200nm and 1600 nm. We demonstrate a strong dependence of the exciton g-factor on the height and diameter of the quantum dots, which eventually gives rise to a sign change of the g-factor. The observed correlation between exciton g-factor and the size of the dots is in good agreement with calculations. Moreover, we find a size dependent anisotropy splitting of the exciton emission in zero magnetic field.Comment: 15 pages, 7 figure

    Entrepreneurship and well-being: the role of national entrepreneurship norm and the importance of meaningfulness at work

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    This study investigates whether entrepreneurship (operationalized as self-employment status) is related to higher levels of meaningfulness at work and individual’s well-being, specifically subjective vitality, when compared to regular employment. We propose that the impact of self-employment on meaningfulness at work would depend on countries’ normative context, namely on the national entrepreneurship prescriptive norm. We analysed 2010’s data from the Global Entrepreneurship Monitor and the European Social Survey on 16 European countries and tested a cross-level moderated mediation model. Results showed that entrepreneurship is positively related to individual’s well-being through the mediating effect of meaningfulness at work. However, the effect of entrepreneurship on individuals’ meaningfulness at work and, ultimately, on their subjective vitality, is stronger for people living in countries with less favorable national entrepreneurship norm. These findings provide evidence for framing meaningfulness at work as being contingent on the interaction between self-employment and national normative context and contribute to the literatures on entrepreneurship, meaningfulness, and well-being at workinfo:eu-repo/semantics/acceptedVersio

    High-performance work systems and individual performance:A longitudinal study of the differential roles of happiness and health well-being

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    As a part of the growing strand of employee-centered HRM research, employee well-being is suggested to be a key mechanism that may help to explain the relationship between HRM and performance. To investigate how an employee’s well-being mediates the HRM-performance relationship, we distinguish between two types of well-being identified in prior work, happiness well-being and health well-being, and present arguments for differences in their effects on individual performance. Building on Job Demands-Resources (JDR) theory, we propose that happiness well-being positively mediates the relationship between perceived High-Performance Work Systems (HPWS) and individual task performance, while health well-being negatively mediates this focal relationship. Thus, happiness well-being fits the “mutual gains” perspective. In contrast, health well-being fits the “conflicting outcomes” perspective, and thus may be harmed by the HPWS to enhance the performance. We find partial support for our arguments in an analysis of longitudinal survey data of 420 participants spanning a total of four waves of data collection

    Indium phosphide based membrane photodetector for optical interconnects on silicon

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    We have designed, fabricated and characterized an InP-based membrane photodetector on an SOI wafer containing a Si-wiring photonic circuit. New results on RF characterization up to 20 GHz are presented. The detector fabrication is compatible with wafer scale processing steps, guaranteeing compatibility towards future generation electronic IC processing

    The influence of human resource practices on perceived work ability and the preferred retirement age: A latent growth modelling approach

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    Organisations are challenged to extend working lives of older workers. However, there is little empirical evidence available on how organisations should do this. This study aims to fill this gap by testing the effect of Human Resource (HR) practices on perceived work ability and the preferred retirement age. Based on the Conversation of Resources theory, we expected that the use of HR practices has a positive effect on perceived work ability and preferred retirement age. We have conducted latent growth curve modelling to test our hypotheses amongst 12,444 employees aged 45 and older at four time points. The results indicate that developmental practices are positively related to work ability, whereas maintenance practices are negatively related to work ability and the preferred retirement age. Accommodative practices are negatively related to the intercepts of both outcomes but not to the slopes, whereas utilisation practices are not related to the outcomes at all.publishedVersio

    Interventions for improving recovery from work

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    ObjectivesThis is a protocol for a Cochrane Review (intervention). The objectives are as follows:To compare the effectiveness of different individual interventions in recovery from work.info:eu-repo/semantics/publishedVersio
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