We demonstrated terahertz imaging using a direct detector based on niobium superconducting tunnel junctions (STJs). The is composed of linearly distributed placed microstrip line and integrated two wings log-periodic antenna. succeeded nondestructive for an integrated-circuit card dry material the around its sensitivity peak (∼0.66THz). dynamic range was measured to be higher than 4×107 (76dB). Thus, STJ applicable high-sensitivity high-speed various inspection applications.

Cellulose nanofiber (CNF)-reinforced polypropylenes (PPs) with different CNF content were investigated by Fourier transform terahertz (THz) spectroscopy over the frequency range of 1–10 THz. Absorption peaks pure PP identified at 3.1, 5.1, 7.5, and 9.6 THz, which indicate isotactic structure is formed. A new peak 7.0 THz appeared when was added, while remained unchanged. Conventional X-ray diffraction (XRD) also performed for comparison. The XRD results do not allow to determine effect in...

We propose a microwave kinetic inductance detector consisting of an NbN rewound spiral resonator (spiral-MKID) as possible broadband terahertz operating with conventional cryogen-free 4He refrigerator. The spiral-MKIDs fabricated films reveal high-Q resonation loaded Q factors on the order 104 at 3 K, and temperature dependence resonance frequency is well fitted by Mattis–Bardeen theory. optical response was confirmed in range below 2.4 THz. also discuss expected noise equivalent power...

We have developed submillimeter-wave direct detectors employing niobium-based superconducting tunnel junctions (STJs), with broadband spectral response, high sensitivity and imaging capability. Spectral response peaked at 650 GHz a fractional bandwidth of 14 percent, which fits one the important atmospheric windows for an astronomical project. also confirmed linearity detector in dynamic range greater than 10/sup 6/. The measured coupling efficiency was about 0.2, lower expected value 0.5....

We designed, fabricated, and characterized a superconducting detector array for terahertz imaging applications. To evaluate the optical performance as an array, we measured spectral response of 5-pixel linear detector, confirmed its sensitivity peaks to be at same frequency within accuracy one percent in range 0.65 THz. The are also good agreement with numerical calculation. This was tested nondestructive metallic pattern integrated-circuit card, allowed shortening total acquisition time....

We have proposed and been developing a new broad-band terahertz (THz) radiation detector using Nb-based superconducting tunnel junction (STJ). The STJ's were fabricated on LiNbO/sub 3/ LiTaO/sub mono-crystal substrates. radiated monochromatic THz pulses in the range 1-2 with pulse repetition rate of 49 Hz, successfully detected corresponding periodic signals via charge-sensitive preamplifier. current signal obtained by derivative output gave time response about 15-20 microseconds. frequency...

We designed and fabricated a microwave kinetic inductance detector (MKID) using niobium nitride (NbN) symmetric spiral resonator array. Previously we revealed that rewound structure works as not only high-Q half-wavelength but also broadband terahertz antenna. conducted simulations for 9 array assuming NbN the superconducting material sapphire dielectric substrate, obtained maximum attenuation of over 30 dB unloaded quality factors 2×105 frequencies between 4.4 4.9 GHz. MKID thin film...

Characteristic poly(<sc>l</sc>-lactide) absorption peaks were identified at 1.8, 4.0, 4.7, and 7.1 THz for an 80 °C crystallization temperature (<italic>T</italic>_c) sample; higher <italic>T</italic>_c resulted in a blue shift of the peak frequency.

SIS photon detectors are niobium-based superconducting direct for submillimeter-wave that show superior performance when compared with bolometric ground-based observations. We present the design and development of together optical cryogenic components wide field continuum observation system on Atacama Submillimeter Telescope Experiment (ASTE). Using antenna coupled distributed junctions, give band response in a 650-GHz atmospheric window as well high current sensitivity, shot noise limited...

High sensitivity submillimeter-wave focal plane array using SIS photon detector is being developed, which we call SISCAM, the superconductive imaging camera. In course of evaluations, have measured performance detectors under various operating conditions. Advantages are explained by nature antenna coupled quantum detectors. Their input coupling can be designed to band-pass characteristics owing distributed junction design. This reduces requirements for infrared blocking filters and enhances...

The principle of a terahertz detector using superconducting tunnel junction (STJ) coupled to large terahertz-absorbing superconductor film is verified. We have detected radiation based on the Cooper-pair breaking process, and confirmed that sensitivity has sharp increase around 0.7 THz, value in agreement with gap frequency Nb. For high-sensitivity detection, we propose an improved design STJ composed smaller thinner film. also discuss expected noise equivalent power optimized detector.

We have developed microwave kinetic inductance detectors (MKIDs) consisting of dual-purpose rewound spirals (spiral-MKIDs) made a metal nitride superconductor for terahertz imaging applications. An NbN-based spiral-MKID array with 25 pixels was fabricated, and the fundamental performance receptivity evaluated at equilibrium temperature conventional 4He refrigerator (3 K). The transmission property showed resonance lines, equally separated by frequency, in range from 2.70 to 2.95 GHz. To...

We investigated microwave characteristics of kinetic inductance detectors (MKIDs) using rewound spiral resonators called as spiral-MKIDs. To realize 25-array spiral-MKIDs, frequency 25 with different resonant frequencies should be equal. proposed spiral-MKIDs expanded and contracted symmetric resonator. conducted simulations for arrays obtained maximum return losses over 12 dB unloaded quality factors 230,000 between 3.2 3.4 GHz. This resonator may useful realization large array MKIDs.

Proposes a character segmentation method for Japanese printed documents. Since is kind of search problem, avoiding 'combinatorial explosion' essential in realizing practical systems. Segmentation very complicated especially when characters touch each other. The described gives multi-stage algorithm, where the earlier stages treat more reliable than later which utilize information obtained from results stages. hypotheses are generated stage on basis stages, and they verified by recognition...

We have developed the superconductive imaging submillimeter-wave camera with nine detector elements (SISCAM-9) for Atacama Submillimeter Telescope Experiment (ASTE). SISCAM-9 has SIS photon detectors as focal plane array at 680 GHz. To obtain background noise limited sensitivity, we need to operate under condition that is dominated by shot of photo current. realize this condition, fabricated low readout circuits using Si-JFETs. In laboratory, evaluated performance detectors. This first...

We propose a YBCO-based microwave kinetic inductance detector with rewound strip structure (spiral-MKID) suitable for imaging applications. The superconducting acts as resonator and broadband antenna. A 25-pixel MKID array width of 10 μm slightly varying length each the resonators was fabricated on 10×10 mm2-MgO substrate. Microwave resonance characteristics were evaluated by measuring one scattering-matrix elements, S21, using vector network analyser. 25 dips clearly observed around 5 GHz;...

We developed a metallic contaminant detector using high-Tc rf-SQUID with Cu pickup coil for industrial products. For manufacturers producing products, problems arising from contaminants are critical issues. A detection system SQUID is powerful tool sensitive inspections. However, since the width dependent on size of SQUID, multiple sensors required practical use. such devices costly and complicated. This reason as to why has not been widely used in field. Therefore, we have recently proposed...

Abstract In this study, poly (L-lactide) (PLLA), (D-lactide) (PDLA), and their blend (stereocomplex; SC) were investigated by terahertz spectroscopy. Absorption spectra obtained for PLLA isothermally crystallized in a temperature range of 80 °C–140 °C, eight characteristic peaks observed the frequency 1–15 THz. No obvious spectral difference between PDLA was observed, indicating that chirality did not affect spectra. Conversely, SC sample exhibited complex peak shift behavior different from...

Submillimeter-wave focal plane arrays based on superconducting direct detectors are designed to be used a new 10-m submillimeter-wave telescope in Chile. Niobium tunnel junctions with low leakage current coupled antenna structures can sensitive when high quantum efficiency and realized. Inhomogeneous distributed log-periodic antennas realize this. Input coupling of better than 50% is calculated bandwidth more 60 GHz using density inhomogeneous junctions. Their measured 5 pA their shot-noise...

Employing an anodization method into our fabrication process, we have successfully fabricated STJs with size of 4 /spl mu/m in diameter, Josephson critical current density 1000 A/cm/sup 2/, low leakage less than 10 pA at 0.3 K and high yield more 90 percent. These were applied to fabricate submillimeter-wave direct detectors using 12 linearly distributed junctions, each circular junction having a 600 2/ diameter. Direct detection submillimeter-waves was measured Fourier transform...

One of the most important factor superconducting tunnel junction for a particle and radiation detection is sub-gap leakage current. An anodization edge an effective method to reduce In new fabrication process Nb/Al-AlO/sub x/-Al/Nb junction, sputtered Al/sub 2/O/sub 3/ layers with 10 nm thickness are used as not only protection layer upper surface both base counter electrodes in process, but also etching stop formation contact hole by reactive ion process.