Keita Ohtani

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We report on high-power terahertz quantum cascade lasers based on low effective electron mass InGaAs/InAlAs semiconductor heterostructures with excellent reproducibility. Growth-related asymmetries in the form of interface roughness and dopant migration play a crucial role in this material system. These bias polarity dependent phenomena are studied using a(More)
Semiconductor quantum dots are potential sources for generating polarization-entangled photons efficiently. The main prerequisite for such generation based on biexciton-exciton cascaded emission is to control the exciton fine-structure splitting. Among various techniques investigated for this purpose, an electric field is a promising means to facilitate the(More)
2×2 parallel fed and 3×3 serial fed patch antenna arrays on a benzocyclobutene (BCB) polymer layer are integrated with a 70 μm wide, dry etched, double metal waveguide quantum cascade laser, operating at about 1.9 THz. The BCB surrounds the quantum cascade laser ridge and is planarized to fit precisely its height. The patch antenna arrays emit a linearly(More)
A high-performance liquid chromatographic method using an electrochemical detector (HPLC-ED) was developed for the determination of nemonapride and its active metabolite, desmethylnemonapride in human plasma. Nemonapride, desmethylnemonapride and moperone chloride, which was used as the internal standard (I.S.) in plasma, were extracted by a rapid and(More)
We propose non-destructive inverse modeling of copper interconnect cross-sectional structures, which reproduces the pitch dependence of intraand interlayer coupling capacitance parasitic to the interconnect. The coupling capacitances, as well as fringing capacitance, are measured by a proposed test structure based on the charge-based capacitance measurement(More)
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