Исследование времени задержки в волноводах из нитрида кремния различной ширины
A new approach to the metrology of optical measurements - the quantum metrology of photons is proposed. The specific character of measurements of the quantum states of polarization of single photons and polarization-entangled photons is considered. The basic problems standing before the contemporary metrology of photons were formulated.
PROCEEDINGS OF SPIE Volume 10912 Physics and Simulation of Optoelectronic Devices XXVII
Bernd Witzigmann Marek Osiński Yasuhiko Arakawa Editors
5–7 February 2019 San Francisco, California, United States
We investigate the absorption properties of U-shaped niobium nitride (NbN) nanowires atop nanophotonic circuits. Nanowires as narrow as 20nm are realized in direct contact with Si3N4 waveguides and their absorption properties are extracted through balanced measurements. We perform a full characterization of the absorption coefficient in dependence of length, width and separation of the fabricated nanowires, as well as for waveguides with different cross-section and etch depth. Our results show excellent agreement with finite-element analysis simulations for all considered parameters. The experimental data thus allows for optimizing absorption properties of emerging single-photon detectors co-integrated with telecom wavelength optical circuits.
For a system of two spatially separated qubits (two-level atoms) coupled to a one-dimensional waveguide we have described the time evolution of singly or doubly excited states of the atomic subsystem. When the interatomic distance l takes special (“resonant” or “antiresonant”) values, the singly excited system of resonant atoms can form metastable (dark) states. If l slightly deviates from one of the special values or the atomic frequencies do not coincide, the dark states slowly decay and we have calculated the decay rate. Also, we have found that the doubly excited state of two resonant atoms located at the special positions does not completely decay but, with a finite probability, can evolve (with the emission of a single photon) to one of the metastable singly excited states. Metastable states of pairs of qubits may find applications (e.g., as memory elements) in information processing or as detectors sensitive to external perturbations.