Long phase-relaxation time in CuCl quantum dots: Four-wave-mixing signals analogous to dye molecules in polymers

Distribution of exciton emission linewidth observed for GaAs quantum dots grown by droplet epitaxy

“…Excitons in semiconductor quantum dots (QDs) may have quite a long phase relaxation time, T 2 , due to discrete energy levels caused by three-dimensional quantum confinement in the nanoscale structures [1][2][3][4][5]. This remarkable feature makes QD excitons a promising candidate for the basic element (qubit) of quantum computation [6][7][8][9].…”

“…We applied stabilized single-photon Fourier spectroscopy to accurately evaluate the exciton linewidth of single quantum dots and found an extremely large distribution of the linewidth ranging from 40 to 400 meV at 4 K. Even the smallest linewidth is not lifetime limited and no correlation was observed between the linewidth and the exciton emission energy. These results are consistent with our previous observation of the strong correlation between the carrier dynamics in the barrier layer and the exciton linewidth of the quantum dots, and imply that the linewidth is not an intrinsic property of genuine quantum dots, but a consequence of their local environment, which can be explained by fluctuating Stark shift caused by photo-excited charged carriers.& 2010 Elsevier B.V. All rights reserved.Excitons in semiconductor quantum dots (QDs) may have quite a long phase relaxation time, T 2 , due to discrete energy levels caused by three-dimensional quantum confinement in the nanoscale structures [1][2][3][4][5]. This remarkable feature makes QD excitons a promising candidate for the basic element (qubit) of quantum computation [6][7][8][9].…”

Third-order optical nonlinearity in ZnO microcrystallite thin films

“…It has been shown that the quantum confinement of the excitons in CdSe or GaAs nanocrystals causes a dramatic reduction in T 2 . 22,23 On the other hand, Kuribayashi et al 24 observed long phase relaxation times in CuCl quantum dots at very low excitation intensity. We have investigated another sample with ϳ352 nm thickness and an average grain size of 120 nm.…”

Self-assembly of quantum dots and rings by droplet epitaxy and their optical properties

“…So, the lowest exciton state and the ground state of the QD can often be dealt with as a two-level system in various kinds of optical processes. Especially the twolevel system is a promising candidate for a qubit (quantum bit) in quantum computation [26][27][28][29], since the dephasing (decoherence) time of the QD exciton is generally long due to the decreased number of electron-phonon scattering channels [31][32][33][34][35], and hence, the coherence of the qubit is maintained for a sufficiently long time to repeat quantum operations.…”