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| Author |
Zhu, J.; Christensen, J.; Jung, J.; Martin-Moreno, L.; Yin, X.; Fok, L.; Zhang, X.; Garcia-Vidal, F. J. |
Title  |
A holey-structured metamaterial for acoustic deep-subwavelength imaging |
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Journal Article |
| Year |
2011 |
Publication |
Nature Physics |
Abbreviated Journal |
Nat. Phys. |
| Volume |
7 |
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1 |
Pages |
52-55 |
| Keywords |
fromIPMRAS |
| Abstract |
For classical waves such as light or sound, diffraction sets a natural limit on how finely the details of an object can be recorded on its image. Recently, various optical superlenses based on the metamaterials concept have shown the possibility of overcoming the diffraction limit. Similar two-dimensional (2D) acoustic hyperlens designs have also been explored. Here we demonstrate a 3D holey-structured metamaterial that achieves acoustic imaging down to a feature size of λ/50. The evanescent field components of a subwavelength object are efficiently transmitted through the structure as a result of their strong coupling with Fabry-Pérot resonances inside the holey plate. This capability of acoustic imaging at a very deep-subwavelength scale may open the door for a broad range of applications, including medical ultrasonography, underwater sonar and ultrasonic non-destructive evaluation. |
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RPLAB @ gujma @ |
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809 |
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Schwaab, G. W.; Hübers, H.-W.; Schubert, J.; Erichsen, Patrik; Gol'tsman, G.; Semenov, A.; Verevkin, A.; Cherednichenko, S.; Gershenzon, E. |
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A high resolution spectrometer for the investigation of molecular structures in the THZ range |
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Conference Article |
| Year |
1999 |
Publication |
Proc. 10th Int. Symp. Space Terahertz Technol. |
Abbreviated Journal |
Proc. 10th Int. Symp. Space Terahertz Technol. |
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530-538 |
| Keywords |
antireflection coatings, dielectric mirrors |
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A status report on the design study of a novel tunable far-infrared (TuFTR) spectrometer for the investigation of the structure of weakly bound molecular complexes is given. The goal is a sensitive TuFIR spectrometer with full frequency coverage from 1-6 THz. To hit the goal, advanced sources (e.g. p-Ge lasers) and detectors (e.g. superconducting hot electron bolometric (HEB) mixers) shall be employed to extend the technique of cavity ringdown spectroscopy, that is currently used at optical and infrared frequencies to the FIR spectral range. Critical for such a system are high-Q resonators that still allow good optical coupling, and wideband antireflection coatings to increase detector sensitivity and decrease optical path losses. 2 nd order effective media theory and an iterative multilayer algorithm have been employed to design wideband antireflection coatings for dielectrics with large dielectric constants like Ge or Si. Taking into account 6 layers, for Si bandwidths of 100% of the center frequency could be obtained with power reflectivities below 1% for both polarizations simultaneously. Wideband dielectric mirrors including absorption losses were also studied yielding a bandwidth of about 50% with reflectivities larger than 99.5%. |
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1577 |
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Tong, C.-Y. Edward; Meledin, Denis; Blundell, Raymond; Erickson, Neal; Kawamura, Jonathan; Mehdi, Imran; Gol'tsman, Gregory |
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A 1.5 THz hot-electron bolometer mixer operated by a planar diode-based local oscillator |
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2003 |
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Proc. 14th Int. Symp. Space Terahertz Technol. |
Abbreviated Journal |
Proc. 14th Int. Symp. Space Terahertz Technol. |
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286 |
| Keywords |
waveguide NbN HEB mixers |
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We describe a 1.5 THz heterodyne receiver based on a superconductin g hot-electron bolometer mixer, which is pumped by an all-solid-state local oscillator chain. The bolometer is fabricated from a 3.5 nm-thick niobium nitride film deposited on a quartz substrate with a 200 nm-thick magnesium oxide buffer layer. The bolometer measures 0.15 fun in width and 1.5 1..tm in length. The chip consisting of the bolometer and mixer circuitry is incorporated in a fixed-tuned waveguide mixer block with a corru g ated feed horn. The local oscillator unit comprises of a cascade of four planar doublers followin g a MMIC-based W-band power amplifier. The local oscillator is coupled to the mixer using a Martin-Puplett interferometer. The local oscillator output power needed for optimal receiver performance is approximately 1 to 2 11W, and the chain is able to provide this power at a number of frequency points between 1.45 and 1.56 THz. By terminating the rf input with room temperature and 77 K loads, a Y-factor of 1.11 (DSB) has been measured at a local oscillator frequency of 1.476 THz at 3 GHz intermediate frequency. |
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1501 |
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Tong, C.-Y. E.; Meledin, D.; Loudkov, D.; Blundell, R.; Erickson, N.; Kawamura, J.; Mehdi, I.; Gol’tsman, G. |
| Title |
A 1.5 THz Hot-Electron Bolometer mixer operated by a planar diode based local oscillator |
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Conference Article |
| Year |
2003 |
Publication |
IEEE MTT-S Int. Microwave Symp. Digest |
Abbreviated Journal |
IEEE MTT-S Int. Microwave Symp. Digest |
| Volume |
2 |
Issue |
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751-754 |
| Keywords |
waveguide NbN HEB mixers |
| Abstract |
We have developed a 1.5 THz superconducting NbN Hot-Electron Bolometer mixer. It is operated by an all-solid-state Local Oscillator comprising of a cascade of 4 planar doublers following an MMIC based W-band power amplifier. The threshold available pump power is estimated to be 1 /spl mu/W. |
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Philadelphia, PA, USA |
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1516 |
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Meledin, D. V.; Marrone, D. P.; Tong, C.-Y. E.; Gibson, H.; Blundell, R.; Paine, S. N.; Papa, D.C.; Smith, M.; Hunter, T. R.; Battat, J.; Voronov, B.; Gol'tsman, G. |
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A 1-THz superconducting hot-electron-bolometer receiver for astronomical observations |
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Journal Article |
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2004 |
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IEEE Trans. Microwave Theory Techn. |
Abbreviated Journal |
IEEE Trans. Microwave Theory Techn. |
| Volume |
52 |
Issue |
10 |
Pages |
2338-2343 |
| Keywords |
NbN HEB mixer, applications |
| Abstract |
In this paper, we describe a superconducting hot-electron-bolometer mixer receiver developed to operate in atmospheric windows between 800-1300 GHz. The receiver uses a waveguide mixer element made of 3-4-nm-thick NbN film deposited over crystalline quartz. This mixer yields double-sideband receiver noise temperatures of 1000 K at around 1.0 THz, and 1600 K at 1.26 THz, at an IF of 3.0 GHz. The receiver was successfully tested in the laboratory using a gas cell as a spectral line test source. It is now in use on the Smithsonian Astrophysical Observatory terahertz test telescope in northern Chile. |
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0018-9480 |
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