Quantum Efficiency of Cold Electron Bolometer Optical Response
Journal article, 2015

In this paper we present the measurements of optical response dependence on power load of a Cold Electron Bolometer integrated in a twin slot antenna. These measurements are also compared to the models of the bolometer limit and the photon counter limit. The responsivity of 0.22*10^9 V/W was measured at 0.22 pW radiation power from a black body at 3.5 K. According to our estimations, for optimized device the voltage responsivity at 100 mK electron temperature can approach Sv=10^10 V/W for power load below 0.1 pW and decreases down to 10^7 V/W at 300 mK for 5 pW signal power in a sample with absorber volume of 5*10^-20 m^3. In the case of low bath temperatures and high applied RF power the changes of tunneling current, dynamic resistance and voltage response are explained by non-thermal energy distribution of excited electrons. Distribution of excited electrons in such system at lower temperatures can be of non-Fermi type, hot electrons with energies of the order of 1 K tunnel from normal metal absorber to superconductor instead of relaxing down to thermal energy kTe in absorber before tunneling. This effect can reduce quantum efficiency of the bolometer at 350 GHz from hf/kTph>100 in ideal case down to single electron per absorbed photon (Q.Eff=1) in the high power case. Methods of preserving high quantum efficiency are discussed.

superconducting devices


submillimeter wave technology

slot antennas



Mikhail Tarasov

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Valerian S. Edelman

Russian Academy of Sciences

Andrey B. Ermakov

National Research University of Electronic Technology (MIET)

Sumedh Mahashabde

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Leonid Kuzmin

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

IEEE Transactions on Terahertz Science and Technology

2156-342X (ISSN) 21563446 (eISSN)

Vol. 5 1 44-48 6991604


Nanofabrication Laboratory

Subject Categories

Condensed Matter Physics



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