Rotation of input polarization arising due to the recombination of electrons from the 1s-excitonic state to the hybrid valence band states have been theoretically examined in asymmetric semiconductor quantum dots. The Jones matrix calculations suggest that the polarization rotation directly depends on the asymmetry of the quantum dot and strength of hh–lh coupling. The results advocate the suitability of quantum dots as polarizing devices.

Polarization rotation in asymmetric semiconductor quantum dots

The invention provides an electromagnetic wave quantum state orbital angular momentum radar detection system and an electromagnetic wave quantum state orbital angular momentum radar detection method.The electromagnetic wave quantum state orbital angular momentum radar detection system comprises a transmitting subsystem and a receiving subsystem, wherein the transmitting subsystem generates electromagnetic wave photons or microwave quanta carrying quantum state orbital angular momentum, selects electromagnetic waves with a required orbital angular momentum modal number, and irradiates a detection target after the electromagnetic waves are transmitted by a quantum electromagnetic wave beamforming antenna; the receiving subsystem uses a light detector to receive reflected photons, or employsan antenna to receive electric field intensity of quantum state orbital angular momentum electromagnetic waves; and a signal processing unit is used for calculating required parameters of the detection target, a signal-to-noise ratio of a signal before detection is increased through data processing and cognitive processing, and finally a signal with a high signal-to-noise ratio is used for completing the functions of radar detection, imaging, tracking and the like. The electromagnetic wave quantum state orbital angular momentum radar detection system and the electromagnetic wave quantum stateorbital angular momentum radar detection method have the advantages of high echo signal power, high signal-to-noise ratio before detection and large scattering sectional area, can improve the detection limit of the traditional radar fundamentally, and improves the detection capability.

Electromagnetic wave quantum state orbital angular momentum radar detection system and method

The invention provides an electromagnetic wave quantum state orbital angular momentum communication system and method. The system comprises a transmitting subsystem and a receiving subsystem. The transmitting subsystem comprises a first high-voltage power supply, a first high-speed electron gun, a first electron cyclotron generation module, an electromagnetic wave modulation module, an orbital angular momentum quantum emitter, an orbital angular momentum mode selector and a beamforming radiator; and the receiving subsystem comprises a second high-voltage power supply, a second high-speed electron gun, a second electron cyclotron generation module, an orbital angular momentum quantum coupler, a diffraction amplification device, an electron sorting device, a receiving demodulator and a dataprocessing unit which are connected in sequence. According to the invention, the orbital angular momentum mode of the electromagnetic wave quantum state can be directly detected, the orbital angular momentum dimension is utilized to transmit data, the data transmission capacity is greatly improved, and the capacity boundary of the traditional antenna receiving electric field intensity is broken through.

Electromagnetic wave quantum state orbital angular momentum communication system and method

We study the effect of spin-orbit interaction for different shape semiconductor quantum nanostructures. The effective one-band Hamiltonian approximation, the position- and energy-dependent quasi-particle effective mass approximation, the finite hard wall confinement potential, and the spin-dependent Ben Daniel-Duke boundary conditions are considered and solved numerically in this work. The spin-orbit interaction which comes from the spin-dependent boundary conditions is characterized for InAs/GaAs quantum dots and quantum rings. We find it can significantly modify the electron energy spectrum for InAs semiconductor quantum dots and quantum rings built in the GaAs matrix. The energy state spin-splitting strongly depends on the geometry of nanostructures. It has an experimentally measurable magnitude for ultra-small quantum dots and quantum rings with non-zero angular momentum.

Electron energy state spin-splitting in nanoscale InAs/GaAs semiconductor quantum dots and rings

In this paper coupling effects and energy spectra are investigated for vertically stacked InAs/GaAs quantum dots under magnetic fields. The Hamiltonian considers here the position- and energy-dependent quasi-particle effective mass approximation and Lande factor, the finite hard wall confinement potential, and the Ben Daniel-Duke boundary conditions. A nonlinear iterative method is applied to solve the three-dimensional problem. For small quantum dots the transition energy is dominated by the number of stacked layers. The inter-distance d between layers plays a crucial role in the tunable states of the dots. For d=1 nm, it is found that there is about 25% variation in ground state energy at zero magnetic field. We observed that the dependence of magnetic fields on the electron transition energy is depressed when the number of vertically coupled layers is increased. This study is constructive for exploring the magneto-optical phenomena and quantum optical structures.

Hsiao-Mei Lu

Papers

Electron energy state spin-splitting in nanoscale InAs/GaAs semiconductor quantum dots and rings

Electronic structure of vertically coupled multilayer semiconductor quantum dots in a magnetic field