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Noise temperature of a 4.3 THz HEB receiver

Khosropanah, P. (author), Laauwen, W.M. (author), Gao, J.R. (author), Hajenius, M. (author), Hovenier, J.N. (author), Klapwijk, T.M. (author)

We have characterized a heterodyne receiver based on an NbN hot electron bolometer integrated with spiral antenna as mixer and an optically pumped FIR ring laser at 4.3 THz as local oscillator (LO). We succeeded in measuring the receiver output power, responding to the hot/cold load, as a function of bias voltage at optimum LO power. From the...

conference paper 2007

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Sensitivity of a hot electron bolometer heterodyne receiver at 4.3 THz

Khosropanah, P. (author), Laauwen, W.M. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author)

We have studied the sensitivity of a superconducting NbN hot electron bolometer mixer integrated with a spiral antenna at 4.3 THz. Using hot/cold blackbody loads and a beam splitter all in vacuum, we measured a double sideband receiver noise temperature of 1300 K at the optimum local oscillator (LO) power of 330 nW, which is about 12 times the...

conference paper 2008

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Heterodyne gas cell measurements at 2.9 THz using a quantum cascade laser as local oscillator

Ren, Y. (author), Gao, J.R. (author), Hovenier, J.N.Higgins, R. (author), Zhang, W. (author), Bell, A. (author), Klein, B. (author), Klapwijk, T.M. (author)

High-resolution heterodyne spectrometers operating at above 2 THz are crucial for detecting, e.g., the HD line at 2.7 THz and oxygen OI line at 4.7 THz in astronomy. The potential receiver technology is a combination of a hot electron bolometer (HEB) mixer and a THz quantum cascade laser (QCL) local oscillator (LO).Here we report the first...

conference paper 2010

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NbN hot electron bolometer mixer at 5.3 THz

Zhang, W. (author), Gao, J.R. (author), Khosropanah, P. (author), Bansal, T. (author), Klapwijk, T.M. (author), Miao, W. (author), Shi, S.C. (author)

We report the sensitivity of a superconducting NbN hot electron bolometer mixer integrated with a tight spiral antenna at 5.3 THz. Using a measurement setup with black body calibration sources and a beam splitter in vacuo, and an antireflection coated Si lens, we obtained a double sideband receiver noise temperature of 1150 K, which is 4.5 times...

conference paper 2010

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Quasiparticle relaxation in high Q superconducting resonators

Barends, R. (author), Van Vliet, S. (author), Baselmans, J.J.A. (author), Yates, S.J.C. (author), Gao, J.R. (author), Klapwijk, T.M. (author)

We present measurements of the quasiparticle relaxation time in Ta superconducting films shaped as planar resonators using the response of the complex conductivity to photon flux. These films have been implanted with magnetic (Mn) as well as non-magnetic atoms (Al). We find a significant decrease of the relaxation time with increasing impurity...

conference paper 2009

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Doubling of sensitivity and bandwidth in phonon cooled hot electron bolometer mixers

Baselmans, J. (author), Hajenius, M. (author), Gao, J. (author), De Korte, P. (author), Klapwijk, T. (author), Voronov, B. (author), Gol'tsman, G. (author)

NbN hot electron bolometer (HEB) mixers are at this moment the best heterodyne detectors for frequencies above 1 THz. However, the fabrication procedure of these devices is such that the quality of the interface between the NbN superconducting film and the contact structure is not under good control. This results in a contact resistance between...

conference paper 2004

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Improved superconducting hot-electron bolometer devices for the THz range

Klapwijk, T.M. (author), Barends, R. (author), Gao, J.R. (author), Hajenius, M. (author), Baselmans, J.J.A. (author)

Improved and reproducible heterodyne mixing (noise temperatures of 950 K at 2.5 THz) has been realized with NbN based hot-electron superconducting devices with low contact resistances. A distributed temperature numerical model of the NbN bridge, based on a local electron and a phonon temperature, has been used to understand the physical...

conference paper 2004

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Frequency locking of single-mode 3.5-THz quantum cascade lasers using a gas cell

Ren, Y. (author), Hovenier, J.N. (author), Cui, M. (author), Hayton, D.J. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Shi, S.C. (author), Kao, T.Y. (author), Hu, Q. (author), Reno, J.L. (author)

We report frequency locking of two 3.5-THz third-order distributed feedback (DFB) quantum cascade lasers (QCLs) by using methanol molecular absorption lines, a proportional-integral-derivative controller, and a NbN bolometer. We show that the free-running linewidths of the QCLs are dependent on the electrical and temperature tuning coefficients....

journal article 2012

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Terahertz heterodyne spectrometer using a quantum cascade laser

Ren, Y. (author), Hovenier, J.N. (author), Higgins, R. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Shi, S.C. (author), Bell, A. (author), Klein, B. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author)

A terahertz (THz) heterodyne spectrometer is demonstrated based on a quantum cascade laser (QCL) as a local oscillator (LO) and an NbN hot electron bolometer as a mixer, and it is used to measure high-resolution molecular spectral lines of methanol (CH3OH) between 2.913–2.918 THz. The spectral lines are taken from a gas cell containing methanol...

journal article 2010

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High-resolution heterodyne spectroscopy using a tunable quantum cascade laser around 3.5 THz

Ren, Y. (author), Hovenier, J.N. (author), Higgins, R. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Shi, S.C. (author), Klein, B. (author), Kao, T.Y. (author), Hu, Q. (author), Reno, J.L. (author)

A frequency tunable terahertz heterodyne spectrometer, based on a third-order distributed feedback quantum cascade laser as a local oscillator, has been demonstrated by measuring molecular spectral lines of methanol (CH3OH) gas at 3.5 THz. By varying the bias voltage of the laser, we achieved a tuning range of ? 1?GHz of the lasing frequency,...

journal article 2011

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Thermal time constant of Nb diffusion-cooled superconducting hot-electron bolometer mixers

Wilms Fleet, D. (author), Gao, J.R. (author), Klapwijk, T.M. (author), de Eorte, P.A.J. (author)

journal article 2001

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Low noise NbN hot electron bolometer mixer at 4.3?THz

Khosropanah, P. (author), Gao, J.R. (author), Laauwen, W.M. (author), Hajenius, M. (author), Klapwijk, T.M. (author)

We have studied the sensitivity of a superconducting NbN hot electron bolometer mixer integrated with a spiral antenna at 4.3?THz. Using hot/cold blackbody loads and a beam splitter all in vacuum, we measured a double sideband receiver noise temperature of 1300?K at the optimum local oscillator (LO) power of 330?nW, which is about 12 times the...

journal article 2007

document

Current-induced vortex unbinding in bolometer mixers

Barends, R. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author)

We present a description of the current-voltage characteristics of hot electron bolometers in terms of the current-dependent intrinsic resistive transition of NbN films. We find that, by including this current dependence, we can correctly predict the complete current-voltage characteristics, showing excellent agreement with measurements for both...

journal article 2005

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IF impedance and mixer gain of NbN hot electron bolometers

Kooi, J.W. (author), Baselmans, J.J.A. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Dieleman, P. (author), Baryshev, A. (author), De Lange, G. (author)

The intermediate frequency (IF) characteristics, the frequency dependent IF impedance, and the mixer conversion gain of a small area hot electron bolometer (HEB) have been measured and modeled. The device used is a twin slot antenna coupled NbN HEB mixer with a bridge area of 1×0.15??m2, and a critical temperature of 8.3?K. In the experiment the...

journal article 2007

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Stability of heterodyne terahertz receivers

Kooi, J.W. (author), Baselmans, J.J.A. (author), Baryshev, A. (author), Schieder, R. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Voronov, B. (author), Gol'tsman, G. (author)

In this paper we discuss the stability of heterodyne terahertz receivers based on small volume NbN phonon cooled hot electron bolometers (HEBs). The stability of these receivers can be broken down in two parts: the intrinsic stability of the HEB mixer and the stability of the local oscillator (LO) signal injection scheme. Measurements show that...

journal article 2006

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Terahertz heterodyne receiver based on a quantum cascade laser and a superconducting bolometer

Gao, J.R. (author), Hovenier, J.N. (author), Yang, Z.Q. (author), Baselmans, J.J.A. (author), Baryshev, A. (author), Hajenius, M. (author), Klapwijk, T.M. (author), Adam, A.J.L. (author), Klaassen, T.O. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author)

We report the first demonstration of an all solid-state heterodyne receiver that can be used for high-resolution spectroscopy above 2?THz suitable for space-based observatories. The receiver uses a NbN superconducting hot-electron bolometer as mixer and a quantum cascade laser operating at 2.8?THz as local oscillator. We measure a double...

journal article 2005

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Contribution of dielectrics to frequency and noise of NbTiN superconducting resonators

Barends, R. (author), Hortensius, H.L. (author), Zijlstra, T. (author), Baselmans, J.J.A. (author), Yates, S.J.C. (author), Gao, J.R. (author), Klapwijk, T.M. (author)

We study NbTiN resonators by measurements of the temperature dependent resonance frequency and frequency noise. Additionally, resonators are studied covered with SiOx dielectric layers of various thicknesses. The resonance frequency develops a nonmonotonic temperature dependence with increasing SiOx layer thickness. The increase in the noise is...

journal article 2008

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Enhancement of quasiparticle recombination in Ta and Al superconductors by implantation of magnetic and nonmagnetic atoms

Barends, R. (author), Van Vliet, S. (author), Baselmans, J.J.A. (author), Yates, S.J.C. (author), Gao, J.R. (author), Klapwijk, T.M. (author)

The quasiparticle recombination time in superconducting films, consisting of the standard electron-phonon interaction and a yet to be identified low-temperature process, is studied for different densities of magnetic and nonmagnetic atoms. For both Ta and Al, implanted with Mn, Ta, and Al, we observe an increase in the recombination rate. We...

journal article 2009

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Frequency and amplitude stabilized terahertz quantum cascade laser as local oscillator

Ren, Y. (author), Hayton, D.J. (author), Hovenier, J.N. (author), Cui, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Shi, S.C. (author), Kao, T.Y. (author), Hu, Q. (author), Reno, J.L. (author)

We demonstrate an experimental scheme to simultaneously stabilize the frequency and amplitude of a 3.5 THz third-order distributed feedback quantum cascade laser as a local oscillator. The frequency stabilization has been realized using a methanol absorption line, a power detector, and a proportional-integral-derivative (PID) loop. The amplitude...

journal article 2012

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Direct detection effect in small volume hot electron bolometer mixers

Baselmans, J.J.A. (author), Baryshev, A. (author), Reker, S.F. (author), Hajenius, M. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Vachtomin, Y. (author), Maslennikov, S. (author), Antipov, S. (author), Voronov, B. (author), Gol'tsman, G. (author)

We measure the direct detection effect in a small volume (0.15??m×1??m×3.5?nm) quasioptical NbN phonon cooled hot electron bolometer mixer at 1.6?THz. We find that the small signal sensitivity of the receiver is underestimated by 35% due to the direct detection effect and that the optimal operating point is shifted to higher bias voltages when...

journal article 2005