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Wang L.,Shanxi University | Tamaki R.,University of Electro - Communications | Kasai K.,Advanced ICT Research Institute | Okada-Shudo Y.,University of Electro - Communications | And 2 more authors.
Laser Physics Letters | Year: 2015

We present a convenient method to generate high quality single-frequency green light at a wavelength of 540 nm. It consists of a noise suppressed external cavity diode laser at a wavelength of 1080 nm by optical filtering and resonant optical feedback, and a frequency doubling of the fundamental light with an a-cut KTP crystal. Highly efficient conversion is realized by type II non-critical phase matching. A stable single-frequency operation with a maximum power of about 20 mW is performed for more than 3 h. Both the intensity noise and line-width reach the level of a monolithic nonplanar ring laser, which is well known for its extraordinarily narrow line-width and extremely low noise among available single-frequency operating lasers. © 2015 Astro Ltd.


Horikawa J.,Ibaraki University | Horikawa J.,Advanced ICT Research Institute | Kawakami A.,Advanced ICT Research Institute | Hyodo M.,Advanced ICT Research Institute | And 3 more authors.
Infrared Physics and Technology | Year: 2014

To improve the response performance of superconducting infrared detectors, we propose using a photonic antenna with a micro-detector in conjunction with a nano-structure. In this paper, we report evaluation results that show the basic characteristics of a photonic antenna in the mid-infrared region. The antenna consists of a nano-slot antenna and a thin-film load resistance placed in the center of the antenna. The antennas were designed for operation at approximately several tens of THz by using an electromagnetic simulator. Through measurements of the spectral reflectance characteristics, clear absorptions caused by the antenna properties were observed at approximately 50 THz, and high polarization dependencies were also observed. The results of the simulation qualitatively agreed with the results of the experiment. The effective area of the antenna was also evaluated and was found to be approximately 3.5 μm2 at 54 THz. © 2014 Published by Elsevier B.V.


Tanaka S.,Advanced ICT Research Institute
Journal of the National Institute of Information and Communications Technology | Year: 2013

By technical progress of nanotechnology and biotechnology in recent years, the target of research is coming to the similar, nano-molecular complexes, and that the idea to use the function of a bio-system substance for bottom up process in nanotechnology has been emerged. Such concepts are promising to produce novel functions of organic materials. In this paper, we introduce the research of nano-scale construction using DNA tiling technology, which is one of the typical examples of bottom up construction with bio-materials.


Aoki I.,Advanced ICT Research Institute | Miki H.,Advanced ICT Research Institute | Otomo A.,Advanced ICT Research Institute
Journal of the National Institute of Information and Communications Technology | Year: 2013

The resent development of organic electro-optic materials and its evaluation techniques are described in the present paper. The molecular design of electro-optic (EO) chromophores to improve the value of hyperpolarizablity (β), which is one of the important parameters to increase the electro-optic coefficient, is described. The hyperpolarizability of newly designed and synthesized EO chromophores was measured by hyper-Rayleigh scattering (HRS) technique, and the discernible improvement in the hyperpolarizability for the new EO chromophores was found. Advantages of the new EO chromophores are also discussed.


Yamashita T.,Advanced ICT Research Institute
Journal of the National Institute of Information and Communications Technology | Year: 2013

Recently, in the various fields such as quantum communication, superconducting nanowire single-photon detectors (SSPD) attract much attention because of their many merits, e.g., high counting rate and so on. However, several parts of important fundamental physics in SSPDs has not been clarified yet. In this work, we measured and analyzed the dark count (error count) of the SSPD in a wide temperature range, and identified its physical origin.


Yamashita T.,Advanced ICT Research Institute | Miki S.,Advanced ICT Research Institute | Terai H.,Advanced ICT Research Institute | Makise K.,Advanced ICT Research Institute | Wang Z.,Advanced ICT Research Institute
IEEE Transactions on Applied Superconductivity | Year: 2013

Toward the realization of a large-scale superconducting nanowire single-photon detector (SSPD) array system, we present the parallel bias operation of an SSPD array in which all elements are simultaneously biased in parallel by a single voltage source. We fabricated an SSPD array with uniform quality and implemented the device with/without single-flux-quantum (SFQ) readout circuit in a compact 0.1 W Gifford-McMahon cryocooler. By applying the time-resolved readout setup, we measured histograms of time-correlated single-photon counts to verify the parallel bias operation of the SSPD array with conventional and SFQ readout techniques. As a result, we confirmed crosstalk-free parallel bias operation of the four-element SSPD array by conventional and SFQ readouts. © 2002-2011 IEEE.


Miki S.,Advanced ICT Research Institute
Journal of the National Institute of Information and Communications Technology | Year: 2013

In the field of various kinds of applications, photon detection technology is one of the key technologies and there is a strong demand to improve detector's performances. Superconducting nanowire single photon detector (SSPD) is expected as a promising candidate to achieve excellent performances (high detection efficiency, fast response speed, short timing jitter, and low dark count rate) as compared to semiconductor avalanche photo diode which is mostly used at present. In this paper, we introduce the mechanism and features of SSPD and report on the development of multichannel SSPD system.


Otomo A.,Advanced ICT Research Institute | Yamada T.,Advanced ICT Research Institute | Inoue S.-I.,Advanced ICT Research Institute
Journal of the National Institute of Information and Communications Technology | Year: 2013

The optical modulation is an essential technology that defines the information transmission speed in the optical communication. Organic electro-optic polymers attract attention because they enable ultra-fast modulation that exceeds 100 GHz with low power consumption. In the Nano ICT Laboratory, we conduct comprehensive research and development of from electro-optic polymer materials to modulators, switches and optical integrated circuit technology towards ultrafast and energy-saving optical communication technology. In this paper, we review the research activities in the electro-optic polymer devices that show rapid progress recently.


Inoue S.-I.,Advanced ICT Research Institute | Otomo A.,Advanced ICT Research Institute
Journal of the National Institute of Information and Communications Technology | Year: 2013

We report the fabrication and device applications of the nonlinear photonic crystals (PhCs) which combines PhC functions for controlling the light dispersion characteristics and highly nonlinear optical organic materials. We reveal a direct relationship between the observed nonlinear optical responses and the corresponding photonic band dispersion nature such as a slow light in the nonlinear PhCs, and we show experimental evidence that the performance of nonlinear optical applications such as the optical switch, wavelength conversion and two-photon absorption devices are dramatically improved in this structure. Moreover, we report on the design and experimental demonstration of an integrated Mach-Zehnder electro-optic (EO) modulator based on the silicon PhC waveguides combined with an EO polymer exhibiting large electro-optic properties.


Hirabayashi M.,Advanced ICT Research Institute | Kawamata I.,University of Tokyo | Hagiya M.,University of Tokyo | Kojima H.,Advanced ICT Research Institute | Oiwa K.,Advanced ICT Research Institute
International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz | Year: 2013

We present an analysis on bond-dissociation dynamics of DNA-based molecular machines under terahertz radiation. Our goal is to control micro/nanoworld utilizing artificial molecular machines. In this work we aim to provide fundamental findings to construct platform technologies to control artificial molecular systems using terahertz waves. © 2013 IEEE.

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