Investigation of Bias Current and Modulation Frequency Dependences of Detectivity of YBCO TES and the Effects of Coating of Cu–C Composite Absorber Layer

Abstract

Bolometric response and noise characteristics of YBCO superconductor transition edge IR detectors with relatively sharp transition and its resulting detectivity are investigated both theoretically and experimentally. The magnitude of response of a fabricated device was obtained for different bias currents and modulation frequencies. Using the measured and calculated bolometric response and noise characteristics, we found and analyzed the device detectivity versus frequency for different bias currents. The detectivity versus chopping frequency of the device did not decrease following the response strongly, due to the decrease of the noise at higher frequencies up to 1 kHz, resulting in maximum detectivity around the modulation frequency of 100 Hz. We also improved the responsivity of the device through the increase of the surface absorption by using a novel infrared absorber, which is made of a copper-carbon composite, coated in a low-temperature process. Within the modulation frequency range studied in this paper, comparison of device detectivity before and after coating is also presented.Index Terms-Detectivity, infrared absorber, transition edge sensor (TES).

Millimeter-Wave Response of All Metal-Organic Deposited YBCO Transition Edge Bolometer

“…Controlling thermal parameters of these detectors can significantly improve their responsivity [21]- [25]. Besides engineering the thermal parameters, the optical properties of the device play an important role in the absorption η and consequently, the responsivity of the device for the target wavelength [26]- [28]. In this section we discuss these affecting parameters on the response of our device.…”

Calculations of Some Doping Nanostructurations and Patterns Improving the Functionality of High-Temperature Superconductors for Bolometer Device Applications

“…Bolometers are radiation sensors that detect incident energy via the increase of the temperature T caused by the absorption of incoming photons [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Bolometers are often used, e.g., for thermal infrared cameras (see, e.g., [1][2][3][4][5][6][7][8][9][10]), mm-wave sensing [1][2][3][4][5][6][8][9][10][11][12][13], space-based [12,13], laboratory far-infrared spectroscopy [13], etc. [1][2][3][4][5][6][7][8][9]…”

“…Bolometers are often used, e.g., for thermal infrared cameras (see, e.g., [1][2][3][4][5][6][7][8][9][10]), mm-wave sensing [1][2][3][4][5][6][8][9][10][11][12][13], space-based [12,13], laboratory far-infrared spectroscopy [13], etc. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Superconductors are among the best candidate materials for bolometers, due to their extreme sensitivity to T near the superconducting transition, measurable for instance through the sharp variations of the electrical resistance R (resistive transition-edge bolometer-TES).…”

“…For resistive TES bolometers, a key figure for performance is the so-called "temperature coefficient of resistance" (TCR), given by [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]:…”

“…After the discovery of high-T c cuprate superconductors (HTS), various authors have explored their use for resistive bolometers with simpler liquid-nitrogen-based cryogenics (the so-called resistive HTS TES bolometers [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]). The compound YBa 2 Cu 3 O δ (YBCO) is the HTS material usually considered for this application, usually with maximum-T c doping, i.e., stoichiometry δ 6.93.…”