Optical and Electrical Characterization of a Large Kinetic Inductance Bolometer Focal Plane Array

Timofeev, A.; Luomahaara, Juho; Grönberg, Leif; Mäyrä, Aki; Sipola, Hannu; Aikio, Mauri; Metso, Mikko; Vesterinen, Visa; Tappura, Kirsi; Ala‐Laurinaho, Juha; Luukanen, Arttu; Hassel, Juha

doi:10.1109/tthz.2016.2639470

Cited by 21 publications

(39 citation statements)

References 14 publications

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“…Each KIB is a lumped-element resonator on a suspended absorptive membrane. The NEP≈10 -14 W/Hz 1/2 was reported for the large array of KIBs 11 . However, due to relatively high AC losses, the resonators provided reasonably high quality factors (Q-factor) only at low frequencies in the range of 100 MHz.…”

mentioning

confidence: 81%

Superconducting noise bolometer with microwave bias and readout for array applications

Kuzmin

Semenov²,

Shitov

et al. 2017

Applied Physics Letters

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We present a superconducting noise bolometer for terahertz radiation, which is suitable for large-format arrays. It is based on an antenna-coupled superconducting micro-bridge embedded in a high-quality factor superconducting resonator for a microwave bias and readout with frequency-division multiplexing in the GHz range. The micro-bridge is kept below its critical temperature and biased with a microwave current of slightly lower amplitude than the critical current of the microbridge. The response of the detector is the rate of superconducting fluctuations, which depends exponentially on the concentration of quasiparticles in the micro-bridge. Excess quasiparticles are generated by an incident THz signal. Since the quasiparticle lifetime increases exponentially at lower operation temperature, the noise equivalent power rapidly decreases. This approach allows for large arrays of noise bolometers operating above 1 K with sensitivity, limited by 300-K background noise. Moreover, the response of the bolometer always dominates the noise of the readout due to relatively large amplitude of the bias current. We performed a feasibility study on a proof-of-concept device with a 1.0 × 0.5 m 2 micro-bridge from a 9-nm thin Nb film on a sapphire substrate. Having a critical temperature of 5.8 K, it operates at 4.2 K and is biased at the frequency 5.6 GHz. For the quasioptical input at 0.65 THz, we measured the noise equivalent power 3×10-12 W/Hz, which is close to expectations for this particular device in the noise-response regime.The demand for sensitive large-format arrays of THz detectors today exists in different terrestrial applications, e.g. THz imaging for non-destructive testing or imaging spectroscopy for material research [1][2][3][4] . The array performance, limited only by the noise of the roomtemperature background radiation (noise equivalent power, NEP photon ≈10-15 W/Hz 1/2 ), is desired at a moderate operation temperature (T b >2 K), which is provided by low-cost and compact cryogenic coolers. Previously, THz imaging arrays with ~10 2 pixels were demonstrated 5,6 . They met the sensitivity requirements, but suffered from rapidly growing complexity of the readout with an increase of the array size. A remarkable example of an array-scalable sensor is the microwave kinetic inductance detector (MKID) 7 , which is based on high-Q superconducting resonators. Along with frequency-division multiplexing (FDM) in the GHz range, this approach allows for building kilo-pixel arrays using powerful software-defined radio (SDR) 8 . However, THzrange pair-braking MKIDs are using superconductors with small energy gap and operating at T b~1 00 mK, which requires expensive and bulky cryogenics. Another type of THz-range array-scalable detector, which is able to work at T b >2 K, is the kinetic inductance bolometer (KIBs) 9,10 . Each KIB is a lumped-element resonator on a suspended absorptive membrane. The NEP≈10 -14 W/Hz 1/2 was reported for the large array of KIBs 11 . However, due to relatively high AC losses, the resonator...

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confidence: 81%

Superconducting noise bolometer with microwave bias and readout for array applications

Kuzmin

Semenov²,

Shitov

et al. 2017

Applied Physics Letters

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“…However, in this region, the requirement for the operating temperature is relaxed to about 5 to 10 K, allowing the use of low-cost cryogenic coolers. The NEP of these detectors is in the order of 10 −15 W/Hz 1/2 [11], higher than the non-equilibrium mode, but sufficient for security applications. Therefore, KIBs provide the possibility of having large FPAs with medium cooled temperature and a reasonable cost for passive imaging [11].…”

Section: A Dual Band Focal Plane Array Of Kinetic Inductance Bolometementioning

confidence: 99%

“…The nonequilibrium mode relies on the finite lifetime of the quasiparticle excitations [8]. Here we concentrate on the kinetic inductance bolometer (KIB) mode in which the superconductor is in a local thermal equilibrium with its surroundings, and the detection is based on the temperature dependence of the inductance [11].…”

Section: Introductionmentioning

confidence: 99%

A Dual-Band Focal Plane Array of Kinetic Inductance Bolometers Based on Frequency-Selective Absorbers

Dabironezare

Hassel

Gandini

et al. 2018

IEEE Trans. THz Sci. Technol.

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Passive imaging cameras at sub-millimeter wavelengths with large format focal plane arrays are being developed as the next generation of security screening systems. In this contribution, a dual-band focal plane array (FPA) for security imagers at submillimeter wave frequencies is presented. The detectors are based on bolometric superconducting kinetic inductance resonators, which allows the development of large FPAs at medium cooled temperatures. Two frequency selective absorber (FSA) sets coupled to superconductive resonator lines are designed to implement a dual color security imager. The performance of the dual band imager is evaluated using spectral analysis approach that combines Fourier optics with a Floquet mode field representation. The geometry of the unit cells is based on a Jerusalem cross configuration and the designed FSAs show a stable angular response and a rejection 1 to 3 of the undesired bandwidth. The detectors in the dual band FPA are distributed over a hexagonal grid to maximize their physical size and then improve their sensitivity. The effective point spread function of the imager coupled to a black body point source over a wide frequency band (1:6) was demonstrated experimentally with excellent agreement to the one estimated by using the proposed spectral technique.Index Terms-Sub-mm wavelengths, focal plane array, frequency selective absorber, incoherent source.

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“…In brief, KIBs are thermal detectors based on sensing the change of the temperature-dependent kinetic inductance on a thermally confined membrane that is heated by the signal absorbed on the membrane. Compared to nonequilibrium KIDs and TESs relying in sub-Kelvin cryogenics, KIBs operate in the temperature range of 5 -10 * Juha.Hassel@vtt.fi K. We have previously demonstrated the scalability into kilo-pixel arrays, and performance in line with the requirements of radiometric imaging of room temperature objects [13]. In this paper, we concentrate on a readout concept suitable for the KIB arrays.…”

Section: Introductionmentioning

confidence: 99%

Multiplexed readout of kinetic inductance bolometer arrays

Sipola

Luomahaara

Timofeev

et al. 2019

Review of Scientific Instruments

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Kinetic inductance bolometer (KIB) technology is a candidate for passive sub-millimeter wave and terahertz imaging systems. Its benefits include scalability into large 2D arrays and operation with intermediate cryogenics in the temperature range of 5 -10 K. We have previously demonstrated the scalability in terms of device fabrication, optics integration, and cryogenics. In this article, we address the last missing ingredient, the readout. The concept, serial addressed frequency excitation (SAFE), is an alternative to full frequency-division multiplexing at microwave frequencies conventionally used to read out kinetic inductance detectors. We introduce the concept, and analyze the criteria of the multiplexed readout avoiding the degradation of the signal-to-noise ratio in the presence of a thermal anti-alias filter inherent to thermal detectors. We present a practical scalable realization of a readout system integrated into a prototype imager with 8712 detectors. This is used for demonstrating the noise properties of the readout. Furthermore, we present practical detection experiments with a stand-off laboratory-scale imager.

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Optical and Electrical Characterization of a Large Kinetic Inductance Bolometer Focal Plane Array

Cited by 21 publications

References 14 publications

Superconducting noise bolometer with microwave bias and readout for array applications

Superconducting noise bolometer with microwave bias and readout for array applications

A Dual-Band Focal Plane Array of Kinetic Inductance Bolometers Based on Frequency-Selective Absorbers

Multiplexed readout of kinetic inductance bolometer arrays

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