Coordination under the Shadow of Career Concerns

To innovate, employees need to develop novel ideas and coordinate with each other to turn these ideas into better products and services. Work outcomes provide signals about employees' abilities to the labor market, and therefore career concerns arise. These can both be 'good' (enhancing incentives for effort in developing ideas) and 'bad' (preventing voluntary coordination). Our model shows how the firm designs its explicit incentive system and organizes work processes to take these conflicting forces into account. The comparative statics results suggest a link between the increased use of teams and recent changes in labor market returns to skills.career concerns, group incentives, knowledge work, reputation, teams

An experimental test of career concerns

Holmström’s (1982/99) career concerns model has become an important workhorse for the analysis of agency issues in many fields. The underlying signal jamming argument requires players to use information in a Bayesian way – which may or may not reasonably approximate real-life decision makers’ behavior. Testing this theory with field data is difficult since typically little is known about the information that individuals base their decisions on, and this explains the dearth of empirical studies. We provide experimental evidence that the signal jamming mechanism works in a laboratory setting. Moreover, subjects’ beliefs fit remarkably well requirements imposed by the Bayesian equilibrium concept.incentives, reputation, career concerns, signal jamming, experiments

InAs quantum dot vertical-cavity lasers

Edge-emitting semiconductor lasers with self-assembled InAs quantum dot (QD) active regions have demonstrated excellent device performance, including low sensitivity to operating temperature and record-low thresholds. In this dissertation, the application of QDs in vertical-cavity lasers (VCLs) is investigated. QDs can reach an emission wavelength up to 1300 nm on GaAs substrate. Key design and device processing issues are discussed and vertical-cavity surface emitting lasers (VCSELs) with both optical and electrical excitation are fabricated. VCSEL diodes with distributed Bragg reflectors (DBRs) formed by selective wet oxidation of AlAs, as well as standard GaAs/AlGaAs mirrors were processed. The latter performed better due to an increased number of QD layers in the cavity. Continuous wave (CW) operation of InAs QD VCSEL diodes with 1 mW output power and threshold current densities below 500 Acm^−2 were achieved. Replacing one of the DBRs with an external spherical mirror, vertical-external cavity surface-emitting lasers (VECSELs) allow the lateral dimensions of the device active region to be increased significantly, yielding high output power while still retaining single mode operation. Pumped by widely available high power diode lasers, QD VECSELs with CW output powers close to 400 mW were demonstrated with threshold pump power densities below 1 kWcm^−2. Since the VECSEL cavity extends into free space, additional optical components can be integrated. By using a non-linear β-Barium Borate (BBO) inside the cavity, we were able to frequency-double the QD emission to produce visible red light, which could be utilized for the red channel of full-color laser projection applications. Despite suboptimal cavity design and minimal heatsinking, output powers over 10 mW at a wavelength of 630 nm were achieved

Renewable Portfolio Standards: Effectiveness and Carbon Implications

A renewable portfolio standard (RPS) policy is a popular regulatory tool implemented within the U.S. and abroad to limit energy sector emissions and incentivize renewable energy. Assessing their effectiveness and efficiency is a key component of achieving further reductions. We assess an energy market under an RPS using fixed-effects panel and 2SLS regression models to lend empirical credence to common theory-based concerns about RPS policy, namely (1) that they leave emissions unregulated once the RPS requirement is met and (2) that they do not incentivize full use of renewable energy resources. Our results show these to be valid concerns that should be considered in the selection, design, and implementation of current or future RPS policies

A wave function based ab initio non-equilibrium Green's function approach to charge transport

We present a novel ab initio non-equilibrium approach to calculate the current across a molecular junction. The method rests on a wave function based description of the central region of the junction combined with a tight binding approximation for the electrodes in the frame of the Keldysh Green's function formalism. In addition we present an extension so as to include effects of the two-particle propagator. Our procedure is demonstrated for a dithiolbenzene molecule between silver electrodes. The full current-voltage characteristic is calculated. Specific conclusions for the contribution of correlation and two-particle effects are derived. The latter are found to contribute about 5% to the current. The order of magnitude of the current coincides with experiments.Comment: 21 pages, 3 figure

Phase sensitive pulse shaping for molecule selective three-photon excitation

In this paper we present a method for selective three-photon excitation of the two dyes, p-Terphenyl (PTP) and BM-Terphenyl (BMT), in solution by using shaped pulses. A good agreement between experiment and theoretical simulation is obtained. With this method it is possible to achieve a considerable change of the Fluorescence contrast between the two dyes which is relevant for imaging applications of biological molecules