Measurement of g-factor tensor in a quantum dot and disentanglement of exciton spins

We perform polarization-resolved magneto-optical measurements on single InAsP quantum dots embedded in an InP nanowire. In order to determine all elements of the electron and hole $g$-factor tensors, we measure in magnetic field with different orientations. The results of these measurements are in good agreement with a model based on exchange terms and Zeeman interaction. In our experiment, polarization analysis delivers a powerful tool that not only significantly increases the precision of the measurements, but also enables us to probe the exciton spin state evolution in magnetic fields. We propose a disentangling scheme of heavy-hole exciton spins enabling a measurement of the electron spin $T_2$ time

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology

Optical Properties of Semiconductor Quantum Dots

This thesis presents different optical experiments performed on semiconductor quantum dots. These structures allow to confine a small number of electrons and holes to a tiny region of space, some nm across. The aim of this work was to study the basic properties of different types of quantum dots made of various materials and with different techniques. First we studied InAsP quantum dots in InP nanowires and demonstrated narrow optical transitions, with linewidths below 30 micro eV. It was also possible to produce electron-hole pairs in a given spin state and to show that, in the presence of a magnetic field, this state is preserved for a time comparable to the exciton lifetime. Measurements of the electron and hole g-factors in these dots are also presented. Other types of structures dealt in this thesis are GaAs quantum dots in AlGaAs and small InAs dots in GaAs. GaAs dots can be tuned to have optical transitions at the same energy as rubidium atoms. We studied InAs quantum rings and we observed energy oscillations that are compatible with the Aharonov-Bohm effect and that can be tuned by an electric field. The last chapter of this thesis deals with two-photon interference, a useful tool for different quantum information protocols. We demonstrated that a InAs quantum dot can emit pairs of indistiguishable photons with a delay of about 5~ns between them.Quantum NanoscienceApplied Science

Sharp emission from single InAs quantum dots grown on vicinal GaAs surfaces

We report on optical studies of single InAs quantum dots grown on vicinal GaAs(001) surfaces. To ensure low quantum dot density and appropriate size, we deposit InAs layers 1.4 or 1.5 ML thick, thinner than the critical thickness for Stranski–Krastanov quantum dot formation. These dots show sharp and bright photoluminescence. Lifetime measurements reveal an exciton lifetime of 500 ps. Polarization measurements show an exciton fine structure splitting of 15??eV and allow to identify the exciton and charged exciton transitions with linewidth as narrow as 23??eV.Kavli Institute of NanoscienceApplied Science

Tuning single GaAs quantum dots in resonance with a rubidium vapor

We study single GaAs quantum dots with optical transitions that can be brought into resonance with the widely used D2 transitions of rubidium atoms. We achieve resonance by Zeeman or Stark shifting the quantum dot levels. We discuss an energy stabilization scheme based on the absorption of quantum dot photoluminescence in a rubidium vapor. This offers a scalable means to counteract slow spectral diffusion in quantum dots.QN/Quantum NanoscienceApplied Science

Measurement of the g-factor tensor in a quantum dot and disentanglement of exciton spins

We perform polarization-resolved magneto-optical measurements on single InAsP quantum dots embedded in an InP nanowire. In order to determine all elements of the electron and hole g-factor tensors, we measure in magnetic fields with different orientations. The results of these measurements are in good agreement with a model based on exchange terms and Zeeman interaction. In our experiment, polarization analysis delivers a powerful tool that not only significantly increases the precision of the measurements, but also enables us to probe the exciton spin-state evolution in magnetic fields. We propose a disentangling scheme of heavy-hole exciton spins enabling a measurement of the electron spin T 2 -time