45 research outputs found

    InAs Quantum Dots of Engineered Height for Fabrication of Broadband Superluminescent Diodes

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    Peer reviewed: YesNRC publication: Ye

    Tuning the electrically evaluated electron Lande g factor in GaAs quantum dots and quantum wells of different well widths

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    We evaluate the Lande g factor of electrons in quantum dots (QDs) fabricated from GaAs quantum well (QW) structures of different well width. We first determine the Lande electron g factor of the QWs through resistive detection of electron spin resonance and compare it to the enhanced electron g factor determined from analysis of the magneto-transport. Next, we form laterally defined quantum dots using these quantum wells and extract the electron g factor from analysis of the cotunneling and Kondo effect within the quantum dots. We conclude that the Lande electron g factor of the quantum dot is primarily governed by the electron g factor of the quantum well suggesting that well width is an ideal design parameter for g-factor engineering QDs

    Stable mode-locked pulses from mid-infrared semiconductor lasers

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    We report the unequivocal demonstration of mid-infrared mode-locked pulses from a semiconductor laser. The train of short pulses was generated by actively modulating the current and hence the optical gain in a small section of an edge-emitting quantum cascade laser (QCL). Pulses with pulse duration at full-width-at-half-maximum of about 3 ps and energy of 0.5 pJ were characterized using a second-order interferometric autocorrelation technique based on a nonlinear quantum well infrared photodetector. The mode-locking dynamics in the QCLs was modelled and simulated based on Maxwell-Bloch equations in an open two-level system. We anticipate our results to be a significant step toward a compact, electrically-pumped source generating ultrashort light pulses in the mid-infrared and terahertz spectral ranges.Comment: 26 pages, 4 figure

    Modeling of an optical memory based on tunable lasers suitable for optical integrated circuits

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    Simulations of two laser systems of which the output wavelength can be switched by optical pulses are presented. The first system is based on two laser cavities containing a phased array waveguide (PHASAR) grating and an optical amplifier, that are coupled with a third optical amplifier. The second system consists of a single laser that contains a PHASAR, amplifier and two or more saturable absorbers. The rate equation model shows that the systems can be switched using pulses with a specific amount of energy. Switching speeds, requirements on the control pulses and the relation with design parameters are discussed

    Guided elastic waves in GaN-on-sapphire

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