Mackillo Kira

Cluster Expansion in Semiconductor Quantum Optics

During recent decades, semiconductor research gradually progressed towards the quantum-optical regime. For example, the special quantum nature of light is apparent when semiconductor quantum dots emit well defined photons [1,2] or when light-matter entanglement influences optical experiments in microcavity structures [3,4].

Pair-Correlation Functions in Incoherent Electron–Hole Plasmas

A density-matrix many-body theory for the description of the interacting electron-hole system in direct-gap semiconductors is presented. The Coulomb interaction between all electrons, the coupling to a quantized light field, and a reservoir of phonons are included. The theory is evaluated to compute the electron-hole and electron-electron correlation functions after initialization of the system as uncorrelated plasma. The dynamical development of pair correlations is discussed.

Correlation effects in the excitonic optical properties of semiconductors

A microscopic many-body theory for the optical and electronic properties of semiconductors is reviewed with an emphasis on the role of correlation effects. At the semiclassical level, the semiconductor Bloch equations include many-body effects via bandgap and field renormalization as well as correlation contributions representing two electron-hole pair amplitudes, excitonic populations, and coupled interband and intraband coherences. These Coulomb interaction induced carrier correlations lead to characteristic signatures in nonlinear semiconductor spectroscopy. At the fully quantum mechanical level the dominant light-matter correlations are described by coupled semiconductor Bloch and luminescence equations. Excitonic emission properties of quantum well and microcavity systems are discussed, including effects such as coherent signatures in the secondary emission and coherent control of the emitted light.

Strong-Field Terahertz Excitations in Semiconductors

Strong-field terahertz excitations in solids non-resonantly create carriers and drive currents in solids on an ultrafast timescale. The resulting combined polarization- and carrier-dynamics are the basis of high-harmonic generation (HHG). A simultaneous resonant optical excitation extends this concept to high-order sideband generation (HSG). Based on a quantum many-body theory of HHG and HSG in solids, we exemplarly demonstrate the spectral and time-resolved properties of solid-state HHG. They include Bloch oscillations and a novel quantum-interference of electrons. Furthermore, we show the capability of HSG to monitor electron–hole recollisions.

Classical and Quantum Optics of Semiconductor Nanostructures

Optical properties of semiconductor nanostructures are widely studied both experimentally and theoretically. They are interesting from an application point of view while they also provide an ideal playground to study Coulomb effects, light–matter interaction, and so forth. For the theoretical modeling, the strongly interacting charge carriers inside a semiconductor present a considerable challenge. This is intensified if also the electromagnetic radiation and potentially also the lattice vibrations have to be treated quantum mechanically. Direct solutions of, e.g., the Schrodinger equation are completely out of question, and a successful theoretical approach has to find consistent methods of truncating the infinite hierarchy problem caused by the interaction. In particular, Coulomb correlations have to be dealt with on the same footing as phonon or photon correlations. Our theoretical approach is based on the Heisenberg equation of motion where the precise density matrix of the total system never has to be known. Instead, we will show in this article how quantum mechanically correct equations of motion can be derived for any quantities of interest as soon as the total system Hamiltonian is known. Thus, the precise knowledge of the Hamilton operator is of utmost importance and it should therefore include all relevant interaction mechanisms of all interacting quasi-particles of interest. Due to this prominent role of the Hamiltonian, we have split this article into two parts. The first two sections deal exclusively with the derivation of the semiconductor Hamiltonian of a nanostructure interacting with both a quantized light field and quantized lattice vibrations. While Section 10.2 deals with the contributions of the non-interacting quasi-particles and introduces important concept of the electronic band structure, the interaction contributions are discussed in Section 10.3. In Section 10.4, we calculate the elementary Heisenberg equation

Physics of semiconductor microcavities and microcavity lasers

The optical properties of semiconductor microcavity systems are studied theoretically on the level of a fully quantum mechanical nonequilibrium theory. The normal mode coupling of the exciton and cavity resonances is investigated for various excitation conditions. Transmission, reflection, photoluminescence, and lasing characteristics are analyzed using the full quantum electrodynamic theory.