A5000248028- Quantum Information and Cryptography
- Semiconductor Quantum Structures and Devices
- Quantum optics and atomic interactions
- Photonic and Optical Devices
- Quantum Mechanics and Applications
- Quantum Computing Algorithms and Architecture
- Quantum and electron transport phenomena
- Terahertz technology and applications
- Semiconductor Lasers and Optical Devices
- Computational Physics and Python Applications
- Advanced Fiber Laser Technologies
- Laser-Matter Interactions and Applications
- Neural Networks and Reservoir Computing
- Nonlinear Optical Materials Studies
- Mechanical and Optical Resonators
- Advanced Photonic Communication Systems
Universität Innsbruck
2022-2024
The quest for the perfect single-photon source includes finding optimal protocol exciting quantum emitter. Coherent optical excitation was, up until now, achieved by tuning laser pulses to transition frequency of emitter, either directly or in average. Recently, it was theoretically discovered that an with two red-detuned is also possible where neither which would yield a significant upper-level population individually. We show so-called swing-up emitter (SUPER) scheme can be implemented...
To coherently control a few-level quantum emitter, typically pulses with an energy resonant to the transition are applied, making use of Rabi mechanism, while single off-resonant pulse does not result in population inversion. Surprisingly, two-color excitation combination two is able invert system. In this paper, we provide in-depth analysis schemes within dressed-state picture. We show that such can be understood as driving between dressed states. two-level system allows us derive analytic...
High-purity multi-photon states are essential for photonic quantum computing. Among existing platforms, semiconductor dots offer a promising route to scalable and deterministic state generation. However, fully realize their potential we require suitable optical excitation method. Current approaches of generation rely on active polarization-switching elements (e.g., electro-optic modulators, EOMs) spatio-temporally demultiplex single photons. Yet, the achievable rate is fundamentally limited...
We report on a multi-photon source based active demultiplexing of single photons emitted from resonantly excited GaAs quantum dot. Active temporal-to-spatial mode demultipexing is implemented via enhanced free-space electro-optic modulators, making it possible to route individual at high switching rates 38 MHz. demonstrate routing into four spatial modes with end-to-end efficiency 79% and measure four-photon coincidence rate 0.17 Hz mostly limited by the single-photon brightness not...
Abstract Nanoscale bright sources that produce high-purity single photons and high-fidelity entangled photon pairs are the building blocks to realize high security quantum communication devices. To achieve rates, it is desirable have an ensemble of emitters can be collectively excited, despite their spectral variability. In case semiconductor dots, Rabi rotations most popular method for resonant excitation. However, these cannot assure a universal, highly efficient excited state preparation,...
Abstract Shaped laser pulses have been remarkably effective in investigating various aspects of light–matter interactions spanning a broad range research. Chirped exhibiting time‐varying frequency, or quadratic spectral phase, form crucial category the group shaped pulses. This type made ubiquitous presence from spectroscopic applications to developments high‐power technology, and nanophotonics quantum optical communication, ever since their introduction. In case technologies recently,...
Quantum communication networks rely on quantum cryptographic protocols including key distribution (QKD) using single photons. A critical element regarding the security of QKD is photon number coherence (PNC), i.e. phase relation between zero and one-photon Fock state, which critically depends excitation scheme. Thus, to obtain flying qubits with desired properties, optimal pumping schemes for emitters need be selected. Semiconductor dots generate on-demand photons high purity...
A scalable source of single photons is a key constituent an efficient quantum photonic architecture. To realize this, it beneficial to have ensemble emitters that can be collectively excited with high efficiency. Semiconductor dots hold great potential in this context due their excellent photophysical properties. Spectral variability commonly regarded as drawback introduced by the fabrication method. However, frequency-multiplexed single-photon platform. Chirped pulse excitation, relying on...
Entangled photon pairs form the foundation for many applications in realm of quantum communication. For fiber-optic transfer entangled pairs, time-bin encoding can potentially offer an improved stability compared to polarization encoded qubits. Here, we lay theoretical foundations describe measurement photons. We derive multi-time correlation functions corresponding state tomographic measurements. Our theory be starting point extend simulations include all kinds loss or decoherence effects...
Because dark excitons in quantum dots are not directly optically accessible, so far they have played a significant role using for photon generation. They possess significantly longer lifetimes than their brighter counterparts and hence offer enormous potential storage or manipulation. In this work, we demonstrate an all-optical retrieval of the spin-forbidden exciton dot from ground state employing chirped pulses in-plane magnetic field. Our experimental findings excellent agreement with...
The sequential resonant excitation of a 2-level quantum system results in the emission state light showing time-entanglement encoded photon-number-basis - notions that can be extended to 3-level systems as discussed recent proposal. Here, we report experimental implementation two-photon process solid-state system, constituted by biexciton-, exciton-, and ground-state semiconductor dot. resulting exhibits entanglement time energy, photon-number basis, which could used information...
The generation of single photons using solid-state quantum emitters is pivotal for advancing photonic technologies, particularly in communication. As the field continuously advances towards practical use cases and beyond shielded laboratory environments, specific demands are placed on robustness light sources during operation. In this context, process against intrinsic extrinsic effects a major challenge. Here, we present robust scheme coherent indistinguishable single-photon states with...
The generation of single photons using solid-state quantum emitters is pivotal for advancing photonic technologies, particularly in communication. As the field continuously advances toward practical use cases and beyond shielded laboratory environments, specific demands are placed on robustness light sources during operation. In this context, process against intrinsic extrinsic effects a major challenge. Here, we present robust scheme coherent indistinguishable single-photon states with very...
Abstract Quantum communication networks rely on quantum cryptographic protocols including key distribution (QKD) using single photons. A critical element regarding the security of QKD is photon number coherence (PNC), i.e. phase relation between zero and one-photon Fock state, which critically depends excitation scheme. Thus, to obtain flying qubits with desired properties, optimal pumping schemes for emitters need be selected. Semiconductor dots generate on-demand photons high purity...
A scalable source of single photons is a key constituent an efficient quantum photonic architecture. To realize this, it beneficial to have ensemble emitters that can be collectively excited with high efficiency. Semiconductor dots hold great potential in this context, due their excellent photophysical properties. Spectral variability commonly regarded as drawback introduced by the fabrication method. However, frequency-multiplexed single-photon platform. Chirped pulse excitation, relying on...
We report on a multi-photon source based active demultiplexing of single photons emitted from resonantly excited GaAs quantum dot. Active temporal-to-spatial mode demultipexing is implemented via enhanced free-space electro-optic modulators, making it possible to route individual at high switching rates 38 MHz. demonstrate routing into four spatial modes with end-to-end efficiency 79% and measure four-photon coincidence rate 0.17 Hz mostly limited by the single-photon brightness not...
For a scalable photonic device producing entangled photons, it is desirable to have multiple quantum emitters in an ensemble that can be collectively excited, despite their spectral variability. dots, Rabi rotation, the most popular method for resonant excitation, cannot assure universal, highly efficient excited state preparation, because of its sensitivity excitation parameters. In contrast, Adiabatic Rapid Passage (ARP), relying on chirped optical pulses, immune dot inhomogeneity. Here,...
To coherently control a few-level quantum emitter, typically pulses with an energy resonant to the transition are applied making use of Rabi mechanism, while single off-resonant pulse does not result in population inversion. Surprisingly, two-color excitation combination two Swing-UP EmitteR (SUPER) mechanism is able invert system. In this paper, we provide in-depth analysis SUPER scheme within dressed-state picture. We show that can be understood as driving between dressed states. two-level...