Pulsed resonance fluorescence and two-photon interference using remote quantum dots

Photonic quantum technology has important applications in quantum computing, simulation and sensing, as well as quantum communication, where photons play the central role as flying qubits. Hereby, two-photon interference of remote sources constitutes a key building block, relying on triggered emission of single and indistinguishable photons. Semiconductor quantum dots are promising, owing to the perspectives of scaling up said technologies on a chip-scale footprint. In this thesis, pulsed resonant excitation was employed to reduce decoherence effects in the solid-state environment, optimizing the two-photon interference of remote quantum dots. Additionally, this study closes the wavelength gap regarding long-distance quantum networking. In this regard, operation in the telecom C-band around 1550 nm is mandatory to match the low-loss wavelength band of optical fibers. This milestone experiment was achieved using quantum frequency conversion for spectral transfer of the pulsed resonance fluorescence of two distinct quantum dots, realizing remote two-photon interference in the telecom C-band. In addition, the gained insights of these experiments motivated the investigation of a novel unipolar quantum dot diode structure. The suppression of blinking and strong reduction of spectral linewidth allowed to demonstrate a concept for active frequency stabilization of the pulsed resonance fluoresence using lock-in amplification, which required critical extensions to previous studies using continuous-wave resonant excitation. In conclusion, the present study offers crucial progress regarding the emission properties and the application of semiconductor quantum dots in key quantum photonic experiments.