Search results for "Quantum ring"
showing 10 items of 12 documents
Wavelet analysis and HHG in nanorings: their applica-tions in logic gates and memory mass devices
2015
We study the application of one nanoring driven by a laser field in different states of polarization in logic circuits. In particular we show that assigning Boolean values to different states of the incident laser field and to the emitted signals, we can create logic gates such as OR, XOR and AND. We also show the possibility of making logic circuits such as half-adder and full-adder using one and two nanorings respectively. Using two nanorings we made the Toffoli gate. Finally we use the final angular momentum acquired by the electron to store information and hence show the possibility of using an array of nanorings as a mass memory device.
Properties of the radiation Emitted by a Laser driven quantum Ring
2015
We present the electromagnetic emission from one electron confined in a quantum ring driven by an intense laser field. We consider both a plain ring and one structured by six potential wells that produce a static tangential force. Through a suitable one-dimensional model we numerically solve the associated Schroedinger equation obtaining the correspondent time evolution of the wave-function. We show that the emission is formed by a wide plateau that can be both quasi-continuum or resolved in discrete lines. We study the dependence of the emitted spectra from the polarization status of the external laser field and in particular we concentrate on the intensity of the emitted lines and of thei…
Quantum ring: HHG spectrum control
2015
Atoms, molecules , clusters and other systems driven by a strong laser field of frequency \omega_L can emit a spectrum of laser harmonics. The high harmonics generation (HHG) phenomen is strongly affected by the symmetries of the system. It is well known that systems with rotational symmetries emit only odd harmonics. Numerous researcher make mainly attention to the possibilities to set different initial conditions in order to control the spectrum. Recently, the study of nanotechnology is hot-topics and in particular the study of very symmetric systems such as fullerene, nanoring and structured nanoring (nanoring with identical and symmetric scattering centers). Therefore, it is natural and…
Temperature dependent optical properties of stacked InGaAs/GaAs quantum rings
2008
4 páginas, 3 figuras, 2 tablas.-- MADICA 2006 Conference, Fifth Maghreb-Europe Meeting on Materials and their Applicatons for Devices and Physical, Chemical and Biological Sensors
Size filtering effect in vertical stacks of In(Ga)As/GaAs self-assembled quantum rings
2006
3 páginas, 3 figuras.
Observation of sequential spin flips in quantum rings
2011
We observe strong signatures of spin flips in quantum rings exposed to external magnetic fields in the Coulomb blockade regime. The signatures appear as a pattern of lines corresponding to local reduction of conductance, and they cover a large range of magnetic fields and number of electrons. The sequence of lines, as well as other features in the conductance, can be captured by many-electron calculations within density-functional theory. The calculations show that most lines in the pattern correspond to sequential spin flips between filling factors 2 and 1. We believe that the ability to probe individual spin flips provides an important step toward precise spin control in quantum ring devi…
Continuum and discrete excitation spectrum of single quantum rings
2005
Photoluminescence and excitation of the photoluminescence spectroscopy has been performed in single InGaAs self-assembled quantum rings embedded in a field effect structure device. To determine their electronic structure, bias-dependent optical transitions have been analyzed both, for individual quantum rings, and for the averaged ensemble. Our results are compared with a theoretical model, and also with results reported by other authors studying similar nanostructures.
Controlling photoemission from laser-driven quantum ring
2015
Defects in quantum ring to control high-harmonic spectrum
2017
AbstractThe high-harmonic generation from a structured quantum ring (SQR) driven by an intense laser field is presented within the single active electron approximation. The spectrum is studied by varying the symmetry of the physical system. The standard SQR (six identical and equidistant dots in a ring) presents a 60° rotational symmetry, that in this work is broken, moving or changing only one potential hole. We find that careful designed breaking of the geometrical symmetry of the SQR opens the possibility of controlling the characteristics of the harmonic lines such as intensity and polarization. HHG analysis of the emission spectrum performed through a Morlet wavelet, shows that the hig…