Superconducting fast microbolometers operating below their critical temperature

Abstract

International audienceno abstrac

Terahertz Direct Detection in ${\hbox{YBa}}_{2}{\hbox{Cu}}_{3}{\hbox{O}}_{7}$ Microbolometers

“…The resulting time constants were approximately the same for both devices, 300 ps±100 ps. Considering the volume of the device, V, and the YBCO specific heat, C [19], at 90 K, we observed that the thermal conductivity from the bolometer to the heat sink (G = C⋅V/τ) was approximately 50 μW/K and 100 μW/K for the 2-μm-and the 4-μm-wide devices. Another method of measuring the thermal conductivity from the bolometer is as discussed in [13].…”

A Room Temperature Bolometer for Terahertz Coherent and Incoherent Detection

“…[17]). Therefore, the response time can be calculated using (9) and results of the thermal conductance measurements from Section V. We obtain a time constant of approximately 2.2 ns.…”

Thermal boundary resistance of YBa2Cu3O7on MgO films deduced from the transientV(I) response

“…The samples to be studied are c-axis oriented YBCO films deposited on crystalline MgO (001) by various methods: dc sputtering, co-evaporation (see reference 6 in [4] for details), and by laser ablation for the samples labelled LEY [2]. The bridge pattern (typically 10 µm wide) was obtained by ion milling after a photolithographic process.…”

“…As was computed by Tinkham [5], and accurately checked by experiment [4], a correction of (2) may be necessary for temperatures far from T c and for I significantly larger than I c . The experimental delay times can then be fitted by (2) or the refined Tinkham's version to provide the gap relaxation time τ , the only unknown parameter.…”

“…The use of high-T c films as bolometers requires knowledge of the thermal properties: the coefficient of heat transfer G, the heat capacity C and the response time τ = C/G [1]. Popular ways of measuring these parameters are the dc method [2], where G is obtained from the power needed to maintain a temperature difference between the film and its substrate, and the transient method [3] in which τ is measured directly as the decay time of the temperature after a sudden excitation. We propose here an entirely different approach using the dynamics of the current-induced transition to the resistive state [4].…”