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40 巻, 7 号
「テラヘルツ波技術の最近の展開」特集号
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「テラヘルツ波技術の最近の展開」特集号
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レーザー解説
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角屋 豊2012 年 40 巻 7 号 p. 479-
発行日: 2012年
公開日: 2020/07/31
ジャーナル フリーPDF形式でダウンロード (184K) -
田中 耕一郎, 廣理 英基2012 年 40 巻 7 号 p. 480-
発行日: 2012年
公開日: 2020/07/31
ジャーナル フリーWe present a review of the recent progress in the generation methods of intense terahertz pulses and their application to THz nonlinear spectroscopy in solids. Especially we pay special attention to large amplitude oscillation of the soft optical phonon mode and carrier multiplication process in semiconductors.抄録全体を表示PDF形式でダウンロード (1962K) -
林 伸一郎, 縄田 耕二, 川瀬 晃道, 南出 泰亜2012 年 40 巻 7 号 p. 486-
発行日: 2012年
公開日: 2020/07/31
ジャーナル フリーWe report on the development of a high-peak-power, single-longitudinal-mode and tunable injectionseeded terahertz-wave parametric generator using MgO:LiNbO3, which operates at room temperature. The high peak power (> 120 W) is enough to allow easy detection by commercial and calibrated pyroelectric detectors, and the spectral resolution (< 5 GHz) is the Fourier transform limit of the subnanosecond terahertz-wave pulse. The tunability (1.2 ‒ 2.8 THz) and the small footprint size (A3 paper, 29.7 × 42 cm) are suitable for a variety of applications.抄録全体を表示PDF形式でダウンロード (1082K) -
尾辻 泰一2012 年 40 巻 7 号 p. 491-
発行日: 2012年
公開日: 2020/07/31
ジャーナル フリーThis paper reviews recent research advances toward the creation of graphene terahertz (THz) lasers. Graphene, a monolayer carbon-atomic honeycomb lattice crystal, has attracted attention due to its superior optoelectronic properties that reflect its massless and gapless energy spectrum. So far we have theoretically and experimentally revealed the occurrence of amplified stimulated THz emission due to negative dynamic conductivity in optically pumped graphene, which will lead to new types of THz lasers. Optical pumping with rather high photon energy of the order of“ ~eV” significantly heats the carriers, which dramatically increases the pumping threshold, preventing population inversion. Current injection pumping is the best solution because electrical pumping can serve any pumping energy, even under the order of“ meV” when a p-i-n junction is formed like semiconductor laser diodes. Dual gate structures can make a p-i-n junction in the graphene channel.抄録全体を表示PDF形式でダウンロード (1886K) -
芹田 和則, 斗内 政吉2012 年 40 巻 7 号 p. 496-
発行日: 2012年
公開日: 2020/07/31
ジャーナル フリーWe have proposed and developed a scanning laser two-dimensional (2D) terahertz (THz) emission imaging system for high-spatial resolution and high-speed measurement. To obtain 2D THz images of the sample, laser pulses are scanned over a 2D THz emitter plate by a galvano meter. In this system, THz wave pulses are locally generated at the laser irradiation spot and transmit through the sample displaced on the emitter. The amplitude of the transmitted THz wave pulse is detected by using a typical THz time-domain spectroscopic technique. Using this system, we have succeeded in obtaining THz transmission images of various samples with a spatial resolution of sub-wavelength order up to 27 μm at an imaging speed of about 47 seconds/image for 512 × 512 pixels. We also investigated the application of the system with metamaterial samples, and observed resonant frequency shifts in transmission spectra. This paper presents a review on the fabricated system.抄録全体を表示PDF形式でダウンロード (3106K) -
今村 元規, 西名 繁樹2012 年 40 巻 7 号 p. 502-
発行日: 2012年
公開日: 2020/07/31
ジャーナル フリーCharacterization of the interaction path of terahertz (THz) waves transmitted through a specifi c material can be applied to non-destructive imaging and testing. The Advantest TAS7000 3D imaging system employs non-destructive imaging technology using computed tomography (CT). This system performs analysis and imaging in both two and three dimensions; enabling identifi cation of specifi c individual materials in a target sample. One important and unique feature of this technology is the non-destructive nature of terahertz spectrum analysis, (non-ionic) thus differing from traditional X-ray CT.抄録全体を表示PDF形式でダウンロード (1561K) -
高野 恵介, 宮丸 文章, 萩行 正憲2012 年 40 巻 7 号 p. 508-
発行日: 2012年
公開日: 2020/07/31
ジャーナル フリーTwo dimensional terahertz metamaterials, which are split-ring resonators and closed-ring resonators, are printed on high-resistivity silicon substrates by super-fine ink-jet printing. The printed samples show band-reject responses that are originated from the resonances of the meta-atoms. By loading the metaatoms to photoconductive antennas, optical switching of the spectrum and polarization of terahertz radiation has been demonstrated. The switching is based on the sensitivity of the resonance of a splitring resonator on a photoconductive substrate to a change in the capacitance induced by optical pulse irradiation. The spectral and polarization characteristics of the split-ring resonator-loaded photoconductive antennas are reasonably explained by the coupling between the electric dipole induced by the pump laser and the resonances of the split-ring resonators.抄録全体を表示PDF形式でダウンロード (1390K)
レーザーオリジナル
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弥永 祐樹, 謝 宜達, 坂口 良幸, 横山 修子, 稲場 肇, 美濃島 薫, 荒木 勉, 安井 武史2012 年 40 巻 7 号 p. 513-
発行日: 2012年
公開日: 2020/07/31
ジャーナル フリーWe observed the hyperfine-structured spectrum of a terahertz (THz) frequency comb with asynchronousoptical- sampling THz time-domain spectroscopy by extending the measured time window of the pulsed THz electric field by up to ten pulse periods. The observed THz comb mode, having a linewidth of 25 MHz and a frequency interval of 250 MHz, can be used as a precise and accurate frequency marker for broadband THz spectrum because it is traceable to a microwave frequency standard via laser control. We further demonstrated THz spectroscopy of sugar tablets and low-pressure water vapor based on THz comb, indicating that the proposed method enables high-accuracy, high-resolution, and broadband THz spectroscopy.抄録全体を表示PDF形式でダウンロード (2047K) -
鈴木 左文, 鏑木 新治, 金谷 英敏, 浅田 雅洋2012 年 40 巻 7 号 p. 517-
発行日: 2012年
公開日: 2020/07/31
ジャーナル フリーRoom temperature terahertz oscillation is reported for resonant tunneling diodes (RTDs) integrated with micro-slot antennas. With an RTD structure for the short transit time of electrons across the collector depletion region, we obtained a fundamental oscillation of up to 1.08 THz. Based on this result, we discuss the structures for further increase in oscillation frequency and demonstrate the effect of an offset slot antenna for high output power. The radiation pattern of the output power of the RTD oscillator on a hyper hemispherical silicon lens was measured and shown to be relatively narrow (around 20 ° in the full width at the half maximum). We also report a preliminary experiment of output power modulation by irradiation of laser light, which is useful for signal transfer from optical fiber communications to terahertz wireless communications.抄録全体を表示PDF形式でダウンロード (1965K)
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