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Hayton, D.J. (author), Khudchenko, A. (author), Pavelyev, D.G. (author), Hovenier, J.N. (author), Baryshev, A. (author), Gao, J.R. (author), Kao, T.Y. (author), Hu, Q. (author), Reno, J.L. (author), Vaks, V. (author)We report on the phase locking of a 3.4 THz third-order distributed feedback quantum cascade laser (QCL) using a room temperature GaAs/AlAs superlattice diode as both a frequency multiplier and an internal harmonic mixer. A signal-to-noise level of 60?dB is observed in the intermediate frequency signal between the 18th harmonic of a 190.7?GHz...journal article 2013
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Braakman, F.R. (author), Barthelemy, P. (author), Reichl, C. (author), Wegscheider, W. (author), Vandersypen, L.M.K. (author)We report both photon- and phonon-assisted tunneling transitions in a linear array of three quantum dots, which can only be understood by considering the full three-dimensionality of the charge stability diagram. Such tunneling transitions potentially contribute to leakage of qubits defined in this system. A detailed understanding of these...journal article 2013
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Cui, M. (author), Hovenier, J.N. (author), Ren, Y. (author), Vercruyssen, N. (author), Gao, J.R. (author), Kao, T.Y. (author), Hu, Q. (author), Reno, J.L. (author)We report on both measurements and simulations of the beam profile and wavefront of a single-mode, 3.5?THz quantum cascade wire laser, incorporating a lateral corrugated metal-metal waveguide, 3rd-order distributed feedback grating. The intrinsic wavefront was measured by using a Hartmann wavefront sensor (HWS) without any optical components...journal article 2013
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Vandersypen, L.M.K. (author), Elzerman, J.M. (author), Schouten, R.N. (author), Willems van Beveren, L.H. (author), Hanson, R. (author), Kouwenhoven, L.P. (author)We observe individual tunnel events of a single electron between a quantum dot and a reservoir, using a nearby quantum point contact (QPC) as a charge meter. The QPC is capacitively coupled to the dot, and the QPC conductance changes by about 1% if the number of electrons on the dot changes by one. The QPC is voltage biased and the current is...journal article 2004
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Zhang, L.X. (author), Leburton, J.P. (author), Hanson, R. (author), Kouwenhoven, L.P. (author)We show that the design of a quantum point contact adjacent to a quantum dot can be optimized to produce maximum sensitivity to single-electron charging in the quantum dot. Our analysis is based on the self-consistent solution of coupled three-dimensional Kohn-Sham and Poisson equations for the quantum circuit. We predict a detection sensitivity...journal article 2004
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Elzerman, J.M. (author), Hanson, R. (author), Willems van Beveren, L.H. (author), Vandersypen, L.M.K. (author), Kouwenhoven, L.P. (author)We demonstrate a method for measuring the discrete energy spectrum of a quantum dot connected very weakly to a single lead. A train of voltage pulses applied to a metal gate induces tunneling of electrons between the quantum dot and a reservoir. The effective tunnel rate depends on the number and nature of the energy levels in the dot made...journal article 2004