Spin singlet and triplet states in a quantum dot molecule

In this dissertation, resonant laser spectroscopy is employed to study coupled electron spins in vertically stacked self-assembled quantum dots. Quantum dots are semiconductor nanostructures with a quantum confinement potential in all spatial direction, leading to an absorption spectrum consisting of narrow lines, similar to the one of atoms. Therefore, quantum dots are well suited to study quantum mechanics at the single emitter level. But in contrast to atoms, quantum dots are embedded in the solid-state. Hence, the physics is enriched by the non-trivial coupling of single spins and charges to the quantum dot environment. Coupling two quantum dots leads to a subtle energy spectrum, enabling more elaborate applications in the so-called field of solid-state quantum optics.