In applications like quantum cryptography and quantum computation, it is desirable to obtain single photon sources which can produce a train of single photons on demand at a high repetition rate, especially at or near room temperature. Such single-photon sources can be realized by tailoring the photonic environment of the quantum emitter. The photonic environment determines the local density of states, into which the photon can be emitted. A number of structures such as interfaces, cavities and waveguides have already been used to modify the spontaneous emission (SE) rate; nevertheless there is still room for improving the overall efficiency of the single-photon sources, e.g., by inventing new ways of enhancing light-matter interaction.
In applications like quantum cryptography and quantum computation, it is desirable to obtain single photon sources which can produce a train of single photons on demand at a high repetition rate, especially at or near room temperature. Such single-photon sources can be realized by tailoring the photonic environment of the quantum emitter. The photonic environment determines the local density of states, into which the photon can be emitted. A number of structures such as interfaces, cavities and waveguides have already been used to modify the spontaneous emission (SE) rate; nevertheless there is still room for improving the overall efficiency of the single-photon sources, e.g., by inventing new ways of enhancing light-matter interaction.
From secure communication to blazingly fast computation, quantum technologies promise arevolutionary horizon with transformative potential across many areas. Single photon sources,essential to utilizing the special qualities of quantum mechanics, are at the core of many ofthese developments. Because single photons are discrete quanta of light, they provide quantum systems withunmatched precision and control, opening up new possibilities for security and sensitivity inapplications like quantum cryptography, quantum key distribution, and quantum sensing.These sources are fundamental components of quantum computing, in which complicatedcomputations can be completed tenfold more quickly than with traditional computers thanks toqubits contained in single photons. To fully realize the promise of quantum technologies andtheir widespread application, single-photon source development and optimization mustcontinue. In the field of quantum technologies, increasing the spontaneous emission rate of a singlephoton source is important for multiple reasons. First of all, a higher emission rate results in amore effective production of single photons, which is necessary for applications like quantumkey distribution (QKD) that demand a high photon flux. A greater emission rate in QKDincreases the overall security and efficiency of quantum communication systems byguaranteeing a quicker and more dependable interchange of quantum information. All things considered, increasing the spontaneous emission rate of a single photon source iscritical to realizing the full promise of quantum technologies, facilitating quicker and moreeffective quantum computing, sensing, integrated photonics, and communication, and openingthe door for revolutionary developments across a range of industries. This thesis explores the impact of electromagnetic scattering on solid-state single photonemitters' spontaneous emission behavior. By applying sophisticated computational approachesand conducting a comprehensive literature analysis, the study seeks to confirm and reproduceprevious findings, expanding and solidifying our knowledge of basic principles andcomputational strategies in this field. Two different scatterer geometries, a sphere, and a cylinder, activated by a point dipoleapproximation that is frequently employed in quantum optics simulations are the subject of thiswork. The main goal is to thoroughly evaluate and validate previously published results, not topresent new physics, but to guarantee the stability and dependability of computational modelsin the study of interactions between light and matter.
Our group recently discovered bright, stable, linearly polarized, and high-purity sources of single-photon emission at room temperature in SiN. Currently, we study the possibility of generating indistinguishable photons by plasmonic speed-up of photoemission, which may enable broader applications of SiN single-photon sources in quantum information technology. The enhancement of the light-matter interaction with plasmonic materials can shorten the spontaneous emission time to beat the dephasing time and achieve coherence even at non-cryogenic temperatures. Our findings spark further studies of quantum emitters toward deeper understanding of their nature, deterministic formation, and scalable integration with on-chip quantum photonic circuitry.
) crystal to realize a new scalable, ultrathin, and efficient SPDC source. By coinciding fundamental and higher order resonances of the metasurface with the generated signal and idler frequencies, respectively, the electric field in the nonlinear media is significantly boosted. This leads to a substantial enhancement in the SPDC process which, subsequently, by using the quantum-classical correspondence principle, translates to very high photon-pair generation rates. The emitted radiation is highly directional and perpendicular to the metasurface in contrast to relevant dielectric structures. The incorporation of circular polarized excitation further increases the photon-pair generation efficiency. The presented work will lead to the design of new efficient ultrathin SPDC single-photon nanophotonic sources working at room temperature that are expected to be critical components in free-space quantum optical communications. In a more general context, our findings can have various applications in the emerging field of quantum plasmonics.
Solid-state sources capable of emitting single photons on demand are of great interest in quantum information applications. Ideally, such a source should emit exactly one photon into the collection optics per trigger, the emitted photons should be indistinguishable, and the source should be electrically driven. Several design strategies addressing these requirements have been proposed. In the cavity-based source, light emission is controlled using resonant cavity quantum electrodynamics effects, whereas in the waveguide-based source, broadband electric field screening effects are employed to direct the light emission into the optical mode of interest. For all the strategies, accurate modeling and careful optical engineering is required to achieve high performance. In this study, we discuss the models and numerical techniques used to analyze such structures. The physical effects governing the light emission profile and the possibilities of tailoring it as well as the mechanisms governing the coherence are elucidated. The major design strategies pursued to optimize the single-photon source performance and the remaining challenges are reviewed.
Control of spontaneously emitted light lies at the heart of quantum optics. It is essential for diverse applications ranging from lasers, light-emitting diodes, solar cells, and quantum information. According to the quantum electrodynamics theory, the spontaneous emission (SE) of an atom can be a weak-coupling radiation process due to the vacuum fluctuations of electromagnetic field. A suitable modification of inhomogeneous environment is required so that the vacuum fluctuations controlling the SE can be manipulated. Inhibiting unwanted SE and boosting desired ones will promote the novel optoelectronic designs tailored to industrial standard. The local density of states (LDOS) counts the number of electromagnetic modes where photons can be emitted at the specific location of the emitter, and can be interpreted as the density of vacuum fluctuations. The inhibition or enhancement of SE boils down to how the LDOS of photons is controlled. In this work, the SE of the excited atoms in 2D arbitrary inhomogeneous environment has been systematically studied. The LDOS determines the radiation dynamics of a point source (for 3D) or a line source (for 2D). In particular, it also determines the SE rate, and the LDOS is represented by the electric dyadic Green’s function. The numerical solution of the electric Green’s tensor has been accurately obtained by the finite-difference frequency-domain method with the proper approximations of the monopole and dipole sources. The SE of the atoms in the photonic crystal and plasmonic metal plates has been comprehensively and comparatively investigated. For both systems, the SE strongly depends on their respective dispersion relations and could be modified or tuned by the finite-structure or finite-size effects. This work is important for the SE engineering and optimized design of optoelectronic devices.