Terahertz imaging with a direct detector based on superconducting tunnel junctions

Ariyoshi, Seiichiro; Otani, Chiko; Dobroiu, Adrian; Sato, Hiromi; Kawase, Kodo; Shimizu, H.M.; Taino, Tohru; Matsuo, Hiroshi

doi:10.1063/1.2204842

Cited by 90 publications

(43 citation statements)

References 8 publications

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“…Although photon counting capabilities in terahertz frequencies were not demonstrated, low leakage junctions can be used to measure fast changing photo currents [12,13]. Low leakage and high impedance tunnel junctions readout by wide bandwidth electronics, photon counting capability should be evaluated.…”

Section: Requirements On Detectorsmentioning

confidence: 99%

Requirements on Photon Counting Detectors for Terahertz Interferometry

Matsuo

2012

J Low Temp Phys

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Future Terahertz astronomy requires higher angular resolution observations. One possibility is to use photon counting interferometry, which is similar to the intensity interferometry demonstrated by Hanbury Brown and Twiss in 1956. In terahertz frequencies, it will be possible to measure all the photon arrivals and can identify bunched photons from thermal sources to measure correlation amplitude and time delay of the photon arrivals. By obtaining the complex visibility, aperture synthesis images can be obtained. I name this technology as photon counting terahertz interferometry (PCTI). From scientific case study, requirements to the detectors are high photon counting rate and accurate time resolution. I discuss on requirements on possible detector technologies such as superconducting single photon detectors (SSPD), superconducting tunnel junction (STJ) detectors and charge sensitive infrared phototransistors (CSIP).

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Section: Requirements On Detectorsmentioning

confidence: 99%

Requirements on Photon Counting Detectors for Terahertz Interferometry

Matsuo

2012

J Low Temp Phys

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“…They are fabricated by lithographic technique and, therefore, can be built into large arrays. Low temperature superconducting (LTS) devices have proven to be the most sensitive detectors [10][11][12][13]. The LTS devices, however, operate at liquid helium (4.2 K) or mK temperatures, requiring complicated and expensive cryogenic instrumentation.…”

Section: Introductionmentioning

confidence: 99%

Terahertz and Millimetre Wave Imaging with a Broadband Josephson Detector Working above 77 K

Hellicar

Hanham

et al. 2010

J Infrared Milli Terahz Waves

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A high-T c superconducting (HTS) broadband Josephson detector has been developed and applied to millimetre wave (mm-wave) and terahertz (THz) imaging. The detector is based on a YBa 2 Cu 3 O 7-x (YBCO) step-edge Josephson junction, which is coupled to a thin-film log-periodic antenna, designed for operation at 200-600 GHz, and a hemispheric silicon lens. The junction parameters have been optimised to achieve a high I c R n value so that the detector responds well to the specified frequencies at liquid nitrogen temperature (77 K). Images at ∼200 GHz and ∼600 GHz were acquired with the same detector; each demonstrated their unique properties. The results demonstrate the potential of achieving a cheaper, compact and portable multi-spectral imager based on a HTS detector.

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“…The SNR is not particularly high here because we use a black body as the source, and the power between the frequency ranges of 0.1 and 1.5 THz is merely several nanowatts. STJ detectors have been reported as being used as THz imaging devices [12]. Compared with other types of detectors, they have the advantages of lower NEP, a greater voltage response, a faster response, a greater dynamic range and ease of use for an array with more pixels.…”

Section: Direct Detector Measurementmentioning

confidence: 99%

A simple Fourier transform spectrometer for terahertz applications

et al. 2012

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A simple Fourier transform spectrometer was designed and constructed for the measurement of detectors, sources, passive devices and materials in the terahertz (THz) range. It can be operated at frequencies between 0.3 and 1.5 THz, using a 50-μm-thick Mylar-film beam splitter. The spectral range can be changed by altering the thickness of the beam splitter. The highest frequency resolution is 750 MHz. We studied the properties of heterodyne detectors including superconductor mixers and semiconductor harmonic mixers, direct detectors including an InSb semiconductor bolometer, superconducting tunnel junctions and the Golay cell, and sources including Gunn oscillators and a microwave source with its multipliers, as well as various materials and passive devices including Si wafers and metal mesh filters. Because of its multiplex and etendue advantages, Fourier transform spectroscopy has become the most efficient way to evaluate the properties of signal sources, samples and detectors in the terahertz (THz) range [1][2][3]. The multiplex advantage is that the interferometer receives information from the entire range of a given spectrum during each time element of a scan, whereas a grating spectrometer receives information from only a narrow band of the spectrum. The etendue advantage is that when the required frequency resolution is much lower than that determined by the throughput, the interferometer has the ability to collect a large amount of energy with no strong limitation on the resolution. This is the situation in the THz range. To evaluate the properties of direct detectors, heterodyne detectors (mixers) and filters fabricated in our laboratory, we designed and constructed a simple Fourier transform spectrometer (FTS) system.

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Terahertz imaging with a direct detector based on superconducting tunnel junctions

Cited by 90 publications

References 8 publications

Requirements on Photon Counting Detectors for Terahertz Interferometry

Requirements on Photon Counting Detectors for Terahertz Interferometry

Terahertz and Millimetre Wave Imaging with a Broadband Josephson Detector Working above 77 K

A simple Fourier transform spectrometer for terahertz applications

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