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Micrograph of a five elements bolometer array. Inset: Scanning electron micrograph of one of the long free standing Nb bridge.
Frequency response to a blackbody source of the SHAB (continuous line) and of a flat-response pyroelectric detector in the same FT-IR setup (dashed line). Arrows indicate the operation frequency of QCLs used for further experiments. Ticks below the SHAB spectrum indicate the position of the main water vapor absorption lines up to 3 THz. Inset: Bolometer characteristics (line) and noise equivalent power (dots).
(a) SHAB response to single pulses from QCL1 (thick lines, at 2.5 THz), and from QCL2 (thin lines, at 4.4 THz). (b) Signal current vs optical power at 1.5 THz (triangle), 2.5 THz (full squares) or 4.4 THz (circles) with linear fits (dotted lines). The full line is the electric responsivity, the top dashed line is the maximum current signal and the bottom dashed line represents the rms noise floor in a 30 Hz bandwidth (see text). (c) Baseline and signal stability of the SHAB illuminated by QCL1 in quasi-cw and incident power of at 2.5 THz during a typical frame acquisition time.
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