My research is focused on solid-state quantum optics. In the past few years I have, for example, investigated methods to collect single photons with near-unity efficiency. Another emphasis is on techniques which can be used to enhance the interaction of a single photon with a single emitter.
Grain Dependent Growth of Bright Quantum Emitters in Hexagonal Boron Nitride
Noah Mendelson,
Luis Morales-Inostroza,
Chi Li,
Ritika Ritika,
Minh Anh Phan Nguyen,
Jacqueline Loyola-Echeverria,
Sejeong Kim,
Stephan Götzinger,
Milos Toth, et al.
Point defects in hexagonal boron nitride have emerged as a promising quantum light source due to their bright and photostable room temperature emission. In this work, the incorporation of quantum emitters during chemical vapor deposition growth on a nickel substrate is studied. Combining a range of characterization techniques, it is demonstrated that the incorporation of quantum emitters is limited to (001) oriented nickel grains. Such emitters display improved emission properties in terms of brightness and stability. These emitters are further utilized and integrated with a compact optical antenna enhancing light collection from the sources. The hybrid device yields average saturation count rates of ≈2.9 × 106 cps and an average photon purity of g(2)(0) ≈ 0.1. The results advance the understanding of single photon emitter incorporation during chemical vapor deposition growth and demonstrate a key step towards compact devices for achieving maximum collection efficiency.
Partial cloaking of a gold particle by a single molecule
Johannes Zirkelbach,
Benjamin Gmeiner,
Jan Renger,
Pierre Türschmann,
Tobias Utikal,
Stephan Götzinger,
Vahid Sandoghdar
Extinction of light by material particles stems from losses incurred by absorption or scattering. The extinction cross section is usually treated as an additive quantity, leading to the exponential laws that govern the macroscopic attenuation of light. In this work, we demonstrate that the extinction cross section of a large gold nanoparticle can be substantially reduced, i.e., the particle becomes<br>more transparent, if a single molecule is placed in its near field. This partial cloaking eect results from a coherent plasmonic interaction between the molecule and the nanoparticle, whereby each of them acts as a nano-antenna to modify the radiative properties of the other.
suggested by editors
Truncated Metallo-Dielectric Omnidirectional Reflector: Collecting Single Photons in the Fundamental Gaussian Mode with 95% Efficiency
Wancong Li,
Luis Morales-Inostroza,
Weiwang Xu,
Pu Zhang,
Stephan Götzinger,
Xue-Wen Chen
We propose a novel antenna structure that funnelssingle photons from a single emitter with unprecedented efficiencyinto a low-divergence fundamental Gaussian mode. Our devicerelies on the concept of creating an omnidirectional photonicbandgap to inhibit unwanted large-angle emission and to enhancesmall-angle defect-guided-mode emission. The new photoncollection strategy is intuitively illustrated, rigorously verified,and optimized by implementing an efficient, body-of-revolution,finite-difference, time-domain method for in-plane dipole emitters.We investigate a few antenna designs to cover various boundaryconditions posed by fabrication processes or material restrictions and theoretically demonstrate that collection efficiencies into thefundamental Gaussian mode exceeding 95% are achievable. Our antennas are broadband, insensitive to fabrication imperfections andcompatible with a variety of solid-state emitters such as organic molecules, quantum dots, and defect centers in diamond.Unidirectional and low-divergence Gaussian-mode emission from a single emitter may enable the realization of a variety of photonicquantum computer architectures as well as highly efficient light−matter interfaces.
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