Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1404.5276

RF heating efficiency of the terahertz superconducting hot-electron bolometer

S. N. Maslennikov

Published Apr 21, 2014• 3 citations
arXivHTMLPDF

Abstract

We report results of the numerical solution by the Euler method of the system of heat balance equations written in recurrent form for the superconducting hot-electron bolometer (HEB) embedded in an electrical circuit. By taking into account the dependence of the HEB resistance on the transport current we have been able to calculate rigorously the RF heating efficiency, absorbed local oscillator (LO) power and conversion gain of the HEB mixer. We show that the calculated conversion gain is in excellent agreement with the experimental results, and that the substitution of the calculated RF heating efficiency and absorbed LO power into the expressions for the conversion gain and noise temperature given by the analytical small-signal model of the HEB yields excellent agreement with the corresponding measured values.

DOI
10.48550/arxiv.1404.5276

Related papers

Rigorous Analysis of a Superconducting Hot-Electron Bolometer Mixer: Theory and Comparison with Experiment

Rainer S. Nebosis, Alexei D. Semenov, Yu. P. Gousev +1 more

We present theoretical analysis of the performance of a superconducting hot-electron bolometer mixer with electron cooling due to electron phonon interaction. The analysis is based on a complete set of thermal balance equations for phonons and electrons. A non-thermal action of a dc current has been considered phenomenologically using an analytical fit of isothermal current-voltage characteristics of the mixer. The operation point of the mixer has been determined as a result of the heating by both the power of a local oscillator and the power dissipated by the current. Electron temperature fluctuations, Nyquist noise, and shot noise have been supposed to only contribute to the mixer noise. The conversion gain and the noise temperature of the mixer have been evaluated taking into account an electro-thermal feedback between the mixer and an intermediate frequency circuit with an arbitrary impedance. We have obtained general expressions for the conversion gain, noise temperature and impedance which enabled us to estimate ultimate performance of a superconducting hot-electron bolometer mixer. Theoretical predictions are in good agreement with experimental results obtained for a NbN hot-electron bolometer mixer at a radiation frequency of 2.5 THz.

Softwaretechnik-Trends•Mar 1, 1996•21 citations

A Hot Spot Mixer Model for Superconducting Phonon-Cooled HEB Far Above the Quasiparticle Bandgap

Harald Merkel, P. Khosropanah, Pavel A. Yagoubov +1 more

Abstract — A hot spot mixer model for phonon cooled hot electron bolometers is set up to accurately determine the dependence of the bolometer resistance on bias and absorbed LO power. An one-dimensional power balance for the nonequilibrium electrons containing an electron heat conduction term along the film and a loss term due to phonon escape to the substrate is solved. In the device's operating region of interest the absorbed heating power is usually large enough to heat a part of the bolometer bridge above the critical temperature forming a normal conducting hot spot. In this model heating due to the LO is assumed to be uniform whereas bias heating takes place in the hot spot region only. Solving the nonlinear power balance for the hot spot length allows to predict current-voltage characteristics, required heating powers and regions of optimal operation. Applying a small signal model in a given operating point yields an estimate for the intrinsic conversion gain. I. LARGE SIGNAL MODEL Existing device models for hot electron bolometers [1,2] treat the bolometer as a lumped element. It is assigned an effective temperature for the phonons and another for the electrons at a given bath temperature. In terms of heating bias power and RF power are equivalent and exchangeable. From this a method [3,4] to calculate the absorbed RF power is derived. This method is referred to as "isotherm " method: Operating points with identical device resistance must have identical temperatures since R(To„,,(,,, ) is a single valued monotonous function. Identical temperature implies identical power losses and identical 592

Softwaretechnik-Trends•Mar 1, 1999•5 citations

Noise and conversion efficiency of aluminum superconducting hot-electron bolometer mixer

Irfan A. Siddiqi, A. Verevkin, D. E. Prober +5 more

We report on microwave measurements of superconducting aluminum hot-electron bolometers (Al HEBs). Diffusion-cooled Al HEB mixers are good candidates for space-borne applications in the Terahertz frequency range since they are predicted to have small local oscillator (LO) power requirements, intermediate frequency (IF) bandwidths /spl gsim/10 GHz, and a noise temperature lower than that of Nb and NbN HEB mixers. Mixer measurements were made at an LO frequency /spl sim/30 GHz, with an IF in the range 0.1 to 7.3 GHz. For T<0.8 K, a magnetic field H=0.1-0.3 T was applied to suppress the superconductivity in the contact pads, and partly in the bridge. For a 0.6 /spl mu/m long device, we measure an IF bandwidth of 4 GHz, a conversion efficiency /spl eta/=-8 dB, and a mixer noise temperature T/sub M//spl gsim/4 K, DSB (T/sub mixer/=T/sub output noise//2/spl eta/). These results are shown to be in quantitative agreement with simple theoretical predictions.

IEEE Transactions on Applied Superconductivity•Mar 1, 2001•17 citations

A Distributed Device Model for Phonon-Cooled HEB Mixers Predicting IV Characteristics, Gain, Noise and IF Bandwidth

P. Khosropanah, H. Merkel, Sigfrid Yngvesson +3 more

A distributed model for phonon-cooled superconductor hot electron bolometer (HEB) mixers is given, which is based on solving the one-dimensional heat balance equation for the electron temperature profile along the superconductor strip. In this model it is assumed that the LO power is absorbed uniformly along the bridge but the DC power absorption depends on the local resistivity and is thus not uniform. The electron temperature dependence of the resistivity is assumed to be continuous and has a Fermi form. These assumptions are used in setting up the non-linear heat balance equation, which is solved numerically for the electron temperature profile along the bolometer strip. Based on this profile the resistance of the device and the IV curves are calculated. The IV curves are in excellent agreement with measurement results. Using a small signal model the conversion gain of the mixer is obtained. The expressions for Johnson noise and thermal fluctuation noise are derived. The calculated results are in close agreement with measurements, provided that one of the parameters used is adjusted.

Softwaretechnik-Trends•May 1, 2000•18 citations

YBaCuO HEB hot-spot model with non-uniform RF power absorption: THz mixing frequency-dependent performance

Romain G. Ladret, Annick F. Degardin, Alain Kreisler

High-TCsuperconductor (YBaCuO) hot electron bolometers (HEB) are promising THz mixers due to the large predicted bandwidth and the low local oscillator (LO) power requirement. Recently, we introduced the hot-spot model, initially dedicated to low-TCNbN devices, to predict YBaCuO mixer performance. Major improvements to the model have been introduced: local description of the power absorption along the HEB constriction, THz dependence of the resistive transition, impedance matching between the THz antenna and the constriction. Mixer noise temperature TNand conversion gain G were predicted up to 2.5 THz. For instance, TN= 2700 K (DSB) and G = -13 dB are obtained with 9 μW of LO power at 1 THz.

International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)•Aug 1, 2015•0 citations

YBCO-Constriction Hot Spot Modeling: DC and RF Descriptions for HEB THz Mixer Noise Temperature and Conversion Gain

Romain G. Ladret, Alain Kreisler, Annick F. Degardin

To investigate the THz mixing performance of YBCO hot electron bolometers (HEB), the influence of the local oscillator (LO) radiofrequency (RF) radiation has been considered in detail. As opposed to the usual hot spot modeling approach, where the LO power is assumed to be uniformly distributed over the HEB constriction length, a uniform RF current has been assumed. The local electron temperature-as obtained by solving the coupled electron and phonon thermal reservoir equations-could then be used to determine the local YBCO complex resistivity, hence the locally dissipated LO power. Besides, the use of a modified two-fluid description allowed to determine the RF-dependent temperature shift (~-1% THz-1) and broadening (~+20% THz-1) of the resistive transition. Finally, the impedance matching to the THz antenna was considered. For a typical constriction, the conversion loss and noise temperature TDSBwere computed, with TDSB× exp(0.32f) behavior up to 2.5 THz.

IEEE Transactions on Applied Superconductivity•Jan 1, 2014•7 citations
We report results of the numerical solution by the Euler method of the system of heat balance equations written in recurrent form for the superconducting hot-electron bolometer (HEB) embedded in an electrical circuit. By taking into account the dependence of the HEB resistance on the transport current we have been able to calculate rigorously the RF heating efficiency, absorbed local oscillator (LO) power and conversion gain of the HEB mixer. We show that the calculated conversion gain is in excellent agreement with the experimental results, and that the substitution of the calculated RF heating efficiency and absorbed LO power into the expressions for the conversion gain and noise temperature given by the analytical small-signal model of the HEB yields excellent agreement with the corresponding measured values.
We present theoretical analysis of the performance of a superconducting hot-electron bolometer mixer with electron cooling due to electron phonon interaction. The analysis is based on a complete set of thermal balance equations for phonons and electrons. A non-thermal action of a dc current has been considered phenomenologically using an analytical fit of isothermal current-voltage characteristics of the mixer. The operation point of the mixer has been determined as a result of the heating by both the power of a local oscillator and the power dissipated by the current. Electron temperature fluctuations, Nyquist noise, and shot noise have been supposed to only contribute to the mixer noise. The conversion gain and the noise temperature of the mixer have been evaluated taking into account an electro-thermal feedback between the mixer and an intermediate frequency circuit with an arbitrary impedance. We have obtained general expressions for the conversion gain, noise temperature and impedance which enabled us to estimate ultimate performance of a superconducting hot-electron bolometer mixer. Theoretical predictions are in good agreement with experimental results obtained for a NbN hot-electron bolometer mixer at a radiation frequency of 2.5 THz.
Abstract — A hot spot mixer model for phonon cooled hot electron bolometers is set up to accurately determine the dependence of the bolometer resistance on bias and absorbed LO power. An one-dimensional power balance for the nonequilibrium electrons containing an electron heat conduction term along the film and a loss term due to phonon escape to the substrate is solved. In the device's operating region of interest the absorbed heating power is usually large enough to heat a part of the bolometer bridge above the critical temperature forming a normal conducting hot spot. In this model heating due to the LO is assumed to be uniform whereas bias heating takes place in the hot spot region only. Solving the nonlinear power balance for the hot spot length allows to predict current-voltage characteristics, required heating powers and regions of optimal operation. Applying a small signal model in a given operating point yields an estimate for the intrinsic conversion gain. I. LARGE SIGNAL MODEL Existing device models for hot electron bolometers [1,2] treat the bolometer as a lumped element. It is assigned an effective temperature for the phonons and another for the electrons at a given bath temperature. In terms of heating bias power and RF power are equivalent and exchangeable. From this a method [3,4] to calculate the absorbed RF power is derived. This method is referred to as "isotherm " method: Operating points with identical device resistance must have identical temperatures since R(To„,,(,,, ) is a single valued monotonous function. Identical temperature implies identical power losses and identical 592
We report on microwave measurements of superconducting aluminum hot-electron bolometers (Al HEBs). Diffusion-cooled Al HEB mixers are good candidates for space-borne applications in the Terahertz frequency range since they are predicted to have small local oscillator (LO) power requirements, intermediate frequency (IF) bandwidths /spl gsim/10 GHz, and a noise temperature lower than that of Nb and NbN HEB mixers. Mixer measurements were made at an LO frequency /spl sim/30 GHz, with an IF in the range 0.1 to 7.3 GHz. For T<0.8 K, a magnetic field H=0.1-0.3 T was applied to suppress the superconductivity in the contact pads, and partly in the bridge. For a 0.6 /spl mu/m long device, we measure an IF bandwidth of 4 GHz, a conversion efficiency /spl eta/=-8 dB, and a mixer noise temperature T/sub M//spl gsim/4 K, DSB (T/sub mixer/=T/sub output noise//2/spl eta/). These results are shown to be in quantitative agreement with simple theoretical predictions.
A distributed model for phonon-cooled superconductor hot electron bolometer (HEB) mixers is given, which is based on solving the one-dimensional heat balance equation for the electron temperature profile along the superconductor strip. In this model it is assumed that the LO power is absorbed uniformly along the bridge but the DC power absorption depends on the local resistivity and is thus not uniform. The electron temperature dependence of the resistivity is assumed to be continuous and has a Fermi form. These assumptions are used in setting up the non-linear heat balance equation, which is solved numerically for the electron temperature profile along the bolometer strip. Based on this profile the resistance of the device and the IV curves are calculated. The IV curves are in excellent agreement with measurement results. Using a small signal model the conversion gain of the mixer is obtained. The expressions for Johnson noise and thermal fluctuation noise are derived. The calculated results are in close agreement with measurements, provided that one of the parameters used is adjusted.
High-TCsuperconductor (YBaCuO) hot electron bolometers (HEB) are promising THz mixers due to the large predicted bandwidth and the low local oscillator (LO) power requirement. Recently, we introduced the hot-spot model, initially dedicated to low-TCNbN devices, to predict YBaCuO mixer performance. Major improvements to the model have been introduced: local description of the power absorption along the HEB constriction, THz dependence of the resistive transition, impedance matching between the THz antenna and the constriction. Mixer noise temperature TNand conversion gain G were predicted up to 2.5 THz. For instance, TN= 2700 K (DSB) and G = -13 dB are obtained with 9 μW of LO power at 1 THz.
To investigate the THz mixing performance of YBCO hot electron bolometers (HEB), the influence of the local oscillator (LO) radiofrequency (RF) radiation has been considered in detail. As opposed to the usual hot spot modeling approach, where the LO power is assumed to be uniformly distributed over the HEB constriction length, a uniform RF current has been assumed. The local electron temperature-as obtained by solving the coupled electron and phonon thermal reservoir equations-could then be used to determine the local YBCO complex resistivity, hence the locally dissipated LO power. Besides, the use of a modified two-fluid description allowed to determine the RF-dependent temperature shift (~-1% THz-1) and broadening (~+20% THz-1) of the resistive transition. Finally, the impedance matching to the THz antenna was considered. For a typical constriction, the conversion loss and noise temperature TDSBwere computed, with TDSB× exp(0.32f) behavior up to 2.5 THz.