NEC

About: NEC is a company organization based out in Tokyo, Japan. It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 33269 authors who have published 57670 publications receiving 835952 citations. The organization is also known as: NEC Corporation & NEC Electronics Corporation.

Apparatus for electroplating the main surface of a substrate

Abstract: An apparatus for electroplating a semiconductor substrate with a metallic film having a uniform thickness. Such a metallic film with a uniform thickness is formed by adjusting the arrangement of the anode so that the intensity distribution of the electric field generating on the main surface to be plated is made substantially uniform. The diameter of the anode is equal to or smaller than one-half that of the main surface of the semiconductor substrate so that the intensity distribution of the electric field on the main surface is substantially uniform. Further, the anode is formed into a mesh which amounts to an area factor equal to or smaller than 50%, which permits the fluctuation of the flux distribution of the plating solution to be neglected.

Distributed-feedback semiconductor laser

Abstract: The distributed-feedback (DFB) semiconductor laser diode comprises an active layer (12) emitting light rays upon injection of an electric current; and an optical waveguide (20) adjoining the active layer, for guiding the light rays together with the active layer (12). The optical waveguide (20) comprises a first semiconductor layer (13) formed in the vicinity of the active layer (12) and having a greater bandgap than that of the active layer (12), whose thickness varies in a corrugation of a prescribed cycle in the direction of the active layer (12), and a second semiconductor layer (14) having a bandgap smaller than that of the first semiconductor layer (13), but greater than that of the active layer (12), and so formed as to confirm the corrugation of the first semiconductor layer (13). First and second cladding layers adjoin the active layer (12) and the optical waveguide (20), respectively, and have bandgaps greater than those of the active layer (12) and of the second semiconductor layer (14). First and second electrodes inject an electric current into the active layer (12) in which a PN junction is formed by forward biasing. Light rays emitted from the active layer (12) interact with the diffraction grating formed by the boundary of the corrugation to receive positive feedback, resulting in laser oscillation in a single longitudinal mode (Fig. 1C).

Terahertz-wave near-field imaging with subwavelength resolution using surface-wave-assisted bow-tie aperture

Abstract: We demonstrate the terahertz-wave near-field imaging with subwavelength resolution using a bow-tie shaped aperture surrounded by concentric periodic structures in a metal film. A subwavelength aperture with concentric periodic grooves, which are known as a bull’s eye structure, shows extremely large enhanced transmission beyond the diffraction limit caused by the resonant excitation of surface waves. Additionally, a bow-tie aperture exhibits extraordinary field enhancement at the sharp tips of the metal, which enhances the transmission and the subwavelength spatial resolution. We introduced a bow-tie aperture to the bull’s eye structure and achieved high spatial resolution (∼λ∕17) in the near-field region. The terahertz-wave near-field image of the subwavelength metal pattern (pattern width=20μm) was obtained for the wavelength of 207μm.

Deterministic photon-photon SWAP gate using a Λ system

Abstract: We theoretically present a method to realize a deterministic photon-photon $\sqrt{\text{SWAP}}$ gate using a three-level $\ensuremath{\Lambda}$ system interacting with single photons in reflection geometry. The $\ensuremath{\Lambda}$ system is used completely passively as a temporary memory for a photonic qubit; the initial state of the $\ensuremath{\Lambda}$ system may be arbitrary, and active control by auxiliary fields is unnecessary throughout the gate operations. These distinct merits make this entangling gate suitable for deterministic and scalable quantum computation.