Terahertz (THz) and sub-terahertz (sub-THz) band detection has a key role in both fundamental interactions physics and technological applications, such as medical imaging, industrial quality control, and homeland security. In particular, transition edge sensors (TESs) and kinetic inductance detectors (KIDs) are the most employed bolometers and calorimeters in the THz and sub-THz band for astrophysics and astroparticles research. Here, we present the electronic, thermal, and spectral characterization of an aluminum/copper bilayer sensing structure that, thanks to its thermal properties and a simple miniaturized design, could be considered a perfect candidate to realize an extremely sensitive class of nanoscale TES (nano-TES) for the giga–terahertz band. Indeed, thanks to the reduced dimensionality of the active region and the efficient Andreev mirror heat confinement, our devices are predicted to reach state-of-the-art TES performance. In particular, as a bolometer the nano-TES is expected to have a noise equivalent power of 5×1020 W/Hz and a relaxation time of 10 ns for the sub-THz band, typical of cosmic microwave background studies. When operated as a single-photon sensor, the devices are expected to show a remarkable frequency resolution of 100 GHz, pointing toward the necessary energy sensitivity requested in laboratory axion search experiments. Finally, different multiplexing schemes are proposed and sized for imaging applications.

1.
G.
Sironi
, “
The frequency spectrum of the cosmic microwave background
,”
New Astron. Rev.
43
,
243
249
(
1999
).
2.
F.
Villaescusa-Navarro
,
S.
Planelles
,
S.
Borgani
,
M.
Viel
,
E.
Rasia
,
G.
Murante
,
K.
Dolag
,
L. K.
Steinborn
,
V.
Biffi
,
A. M.
Beck
, and
C.
Ragone-Figueroa
, “
Neutral hydrogen in galaxy clusters: Impact of AGN feedback and implications for intensity mapping
,”
Mon. Not. R. Astron. Soc.
456
,
3553
3570
(
2016
).
3.
I. G.
Irastorza
and
J.
Redondo
, “
New experimental approaches in the search for axion-like particles
,”
Prog. Part. Nucl. Phys.
102
,
89
(
2018
).
4.
U.
Seljak
and
M.
Zaldarriaga
, “
Signature of gravity waves in the polarization of the microwave background
,”
Phys. Rev. Lett.
78
,
2054
(
1997
).
5.
M.
Kamionkowski
and
E. D.
Kovetz
, “
The quest for B modes from inflationary gravitational waves
,”
Annu. Rev. Astron. Astroph.
54
,
227
269
(
2016
).
6.
L.
Armus
,
V.
Charmandaris
, and
B. T.
Soifer
, “
Observations of luminous infrared galaxies with the Spitzer Space Telescope
,”
Nat. Astron.
4
,
467
477
(
2020
).
7.
A.
Ringwald
, “
Exploring the role of axions and other WISPs in the dark universe
,”
Phys. Dark Univ.
1
,
116
135
(
2012
).
8.
L. M.
Capparelli
,
G.
Cavoto
,
J.
Ferretti
,
F.
Giazotto
,
A. D.
Polosa
, and
P.
Spagnolo
, “
Axion-like particle searches with sub-THz photons
,”
Phys. Dark Univ.
12
,
37
44
(
2016
).
9.
M.
Arik
et al., “
New solar axion search using the CERN Axion Solar Telescope with 4He filling
,”
Phys. Rev. D
92
,
021101
(
2015
).
10.
E.
Armengaud
et al., “
Conceptual design of the International Axion Observatory (IAXO)
,”
JINST
9
,
T05002
(
2014
).
11.
K. D.
Irwin
, “
Seeing with superconductors
,”
Sci. Am.
295
,
86
94
(
2006
).
12.
K. D.
Irwin
, “
An application of electrothermal feedback for high resolution cryogenic particle detection
,”
Appl. Phys. Lett.
66
,
1998
(
1995
).
13.
B. S.
Karasik
and
R.
Cantor
, “
Demonstration of high optical sensitivity in far-infrared hot-electron bolometer
,”
Appl. Phys. Lett.
98
,
193503
(
2011
).
14.
A.
Monfardini
et al.,
Proc. SPIE
9914
,
99140N
(
2016
).
15.
P.
Khosropanah
et al.,
Proc. SPIE
7741
,
77410L
(
2010
).
16.
P.
de Visser
,
J.
Baselmans
,
J.
Bueno
et al., “
Fluctuations in the electron system of a superconductor exposed to a photon flux
,”
Nat. Commun.
5
,
3130
(
2014
).
17.
J.
Wei
,
D.
Olaya
,
B. S.
Karasik
,
S. V.
Pereverzev
,
A. V.
Sergeev
, and
M. E.
Gershenson
, “
Ultrasensitive hot-electron nanobolometers for terahertz astrophysics
,”
Nat. Nanotechnol.
3
,
496
500
(
2008
).
18.
R.
Kokkoniemi
et al., “
Nanobolometer with ultralow noise equivalent power
,”
Commun. Phys.
2
,
124
(
2019
).
19.
L. S.
Kuzmin
et al., “
Photon-noise-limited cold-electron bolometer based on strong electron self-cooling for high-performance cosmology missions
,”
Commun. Phys.
2
,
104
(
2019
).
20.
P.
Virtanen
,
A.
Ronzani
, and
F.
Giazotto
, “
Josephson photodetectors via temperature-to-phase conversion
,”
Phys. Rev. Appl.
9
,
054027
(
2018
).
21.
F.
Paolucci
,
N.
Ligato
,
V.
Buccheri
,
G.
Germanese
,
P.
Virtanen
, and
F.
Giazotto
, “
Hypersensitive tunable Josephson escape sensor for gigahertz astronomy
,”
Phys. Rev. Appl.
14
,
034055
(
2020
).
22.
D.
Alesini
et al., “
Status of the SIMP project: Toward the single microwave photon detection
,”
J. Low Temp. Phys.
199
,
348
354
(
2020
).
23.
T.
Bergmann
, “Energy resolving power of transition edge x-ray microcalorimeters,” Ph.D. dissertation (University of Utrecht, 2004).
24.
A. F.
Andreev
, “
The thermal conductivity of the intermediate state in superconductors
,”
Sov. Phy. JETP
19
,
1228
1231
(
1964
).
25.
Q.
Sun
,
Y.
He
,
K.
Liu
,
S.
Fan
,
E. P. J.
Parrott
, and
E.
Pickwell-MacPherson
, “
Recent advances in terahertz technology for biomedical applications
,”
Quant. Imaging Med. Surg.
7
,
345
355
(
2017
).
26.
F.
Ellrich
,
M.
Bauer
,
N.
Schreiner
et al., “
Terahertz quality inspection for automotive and aviation industries
,”
J. Infrared Millim. Terahertz Waves
41
,
470
489
(
2020
).
27.
A.
Rogalski
and
F.
Sizov
, “
Terahertz detectors and focal plane arrays
,”
Opto-Electron. Rev.
19
,
346
(
2011
).
28.
M.
Tinkham
,
Introduction to Superconductivity
(
McGraw Hill
,
1996
).
29.
F.
Giazotto
,
T. T.
Heikkila
,
A.
Luukanen
,
A. M.
Savin
, and
J. P.
Pekola
, “
Opportunities for mesoscopics in thermometry and refrigeration: Physics and applications
,”
Rev. Mod. Phys.
78
,
217
274
(
2006
).
30.
H.
Courtois
,
M.
Meschke
,
J. T.
Peltonen
, and
J. P.
Pekola
, “
Origin of hysteresis in a proximity Josephson junction
,”
Phys. Rev. Lett.
101
,
067002
(
2008
).
31.
J. F.
Cochran
and
D. E.
Mapother
, “
Superconducting transition in aluminum
,”
Phys. Rev.
111
,
132
(
1958
).
32.
P. G.
De Gennes
, “
Boundary effects in superconductors
,”
Rev. Mod. Phys.
36
,
225
(
1964
).
33.
V. G.
Kogan
, “
Coherence length of a normal metal in a proximity system
,”
Phys. Rev. B
26
,
88
(
1982
).
34.
R.
Meservey
and
P. M.
Tedrow
, “
Properties of very thin aluminum films
,”
J. Appl. Phys.
42
,
51
(
1971
).
35.
F. C.
Wellstood
,
C.
Urbina
, and
J.
Clarke
,
Phys. Rev. B
49
,
5942
(
1994
).
36.
R.
Bosisio
,
P.
Solinas
,
A.
Braggio
, and
F.
Giazotto
, “
Photonic heat conduction in Josephson-coupled Bardeen-Cooper-Schrieffer superconductors
,”
Phys. Rev. B
93
,
144512
(
2016
).
37.
T. T.
Heikkilä
,
M.
Hatamib
, and
G. E. W.
Bauerb
, “
Electron–electron interaction induced spin thermalization in quasi-low-dimensional spin valves
,”
Solid State Commun.
150
,
475
(
2010
).
38.
K. D.
Irwin
and
G. C.
Hilton
, Cryogenic Particle Detection, Topics in Applied Physics Vol. 99 (Springer, 2005).
39.
K. D.
Irwin
, “Phonon-mediated particle detection using superconducting tungsten transition-edge sensors,” Ph.D. thesis (Stanford University, 1995).
40.
J. C.
Mather
, “
Bolometer noise: Nonequilibrium theory
,”
Appl. Opt.
21
,
1125
1129
(
1982
).
41.
S.
Lee
,
J. M.
Gildemeister
,
W.
Holmes
,
A. T.
Lee
, and
P. L.
Richards
, “
Voltage-biased superconducting transition-edge bolometer with strong electrothermal feedback operated at 370 mK
,”
Appl. Opt.
37
,
3391
3397
(
1998
).
42.
K.
Morgan
, “
Hot science with cool sensors
,”
Phys. Today
71
,
28
34
(
2018
).
43.
J. N.
Ullom
and
D. A.
Bennet
, “
Review of superconducting transition-edge sensors for x-ray and gamma-ray spectroscopy
,”
Supercond. Sci. Technol.
28
,
084003
(
2015
).
44.
T. M.
Lanting
,
H.
Cho
,
J.
Clarke
,
M.
Dobbs
,
A. T.
Lee
,
P. L.
Richards
,
H.
Spieler
, and
A.
Smith
,
Proc. SPIE
4855
,
172
181
(
2003
).
45.
A.
Tartari
,
A. M.
Baldini
,
F.
Cei
,
L.
Galli
,
M.
Grassi
,
D.
Nicol
,
M.
Piendibene
,
F.
Spinella
,
D.
Vaccaro
, and
G.
Signorelli
, “
Development and testing of the FDM read-out of the TES arrays aboard the LSPE/SWIPE balloon-borne experiment
,”
J. Low Temp. Phys.
199
,
212
218
(
2020
).
46.
J.
Yoon
,
J.
Clarke
,
J. M.
Gildemeister
,
A. T.
Lee
,
M. J.
Myers
,
P. L.
Richards
, and
J. T.
Skidmore
, “
Single superconducting quantum interference device multiplexer for arrays of low-temperature sensors
,”
Appl. Phys. Lett.
78
,
371
(
2001
).
47.
M.
Mück
,
M.-O.
Andr
, and
J.
Clarke
, “
Radio-frequency amplifier based on a niobium dc superconducting quantum interference device with microstrip input coupling
,”
Appl. Phys. Lett.
72
,
2885
(
1998
).
48.
M. E.
Huber
et al., “
DC SQUID series array amplifiers with 120 MHz bandwidth
,”
IEEE Trans. Appl. Supercond.
1
,
1251
1256
(
2001
).
49.
A. M.
Dobbs
et al., “
Frequency multiplexed SQUID readout of large bolometer arrays for cosmic microwave background measurements
,”
Rev. Sci. Instrum.
83
,
073113
(
2012
).
You do not currently have access to this content.