Development of terahertz wave detector using superconducting tunnel junction (original) (raw)
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Terahertz imaging with a direct detector based on superconducting tunnel junctions
Applied Physics Letters, 2006
We demonstrated terahertz imaging using a direct detector based on niobium superconducting tunnel junctions ͑STJs͒. The detector is composed of linearly distributed junctions placed on a superconducting microstrip line and is integrated on two wings of a log-periodic antenna. We succeeded nondestructive imaging for an integrated-circuit card and dry material using the detector around its sensitivity peak ͑ϳ0.66 THz͒. The dynamic range was measured to be higher than 4 ϫ 10 7 ͑76 dB͒. Thus, the STJ detector is applicable to high-sensitivity and high-speed terahertz imaging for various nondestructive inspection applications.
THz photon detectors with superconducting tunnel junctions
Terahertz Photonics, 2007
Superconducting tunnel junctions, which are also known as superconductor-insulator-superconductor (SIS) junctions, are widely used in coherent detection (heterodyne mixing) of electromagnetic radiation at millimeter and submillimeter wavelengths to achieve high spectral resolution (∆ν/ν<10 -6 ). With extremely low dark current and high quantum efficiency, superconducting tunnel junctions are also promising for THz photon detection. Besides the merit of high detection sensitivity, THz photon detectors with superconducting tunnel junctions can be operated at relatively high temperatures (above 0.3 K) and don't need rather complicated filtering systems by simply incorporating a superconducting resonant circuit with superconducting tunnel junctions. This paper mainly investigates the characteristics of THz photon detectors with Nb and NbN-based superconducting tunnel junctions. The MAR effect and associated shot noise are addressed. Some analytical and preliminary experimental results are presented.
Proceedings of the IEEE, 2020
At terahertz (THz) frequencies, between 0.1-10 THz, current compact emitter and receiver technologies are generally inefficient and impractical. Hence, a gap exists between mature microwave and developed optical technologies. On-chip, integrated broadly tunable and powerful quantum sources that coherently radiate THz waves between 0.1 and 11 THz (potentially extendable to 15 THz) and with potential output power of > 1 mW can be achieved based on quantum tunneling of electron pairs across the stack of intrinsic Josephson junctions (IJJs) naturally present in a single crystal of the layered high-Tc superconducting Bi2Sr2CaCu2O+ (BSCCO). Such devices have been found to be especially promising solid-state THz sources capable of bridging the entire THz gap, as their wide frequency tunability range is superior to that obtained from their semiconducting based rivals, either single resonant tunneling diodes (RTDs) or THz-quantum cascade lasers (QCLs). Due to the unique electrodynamics of BSCCO, they can also be operated as switching current detectors, paving the way for the realization of on-chip THz integrated circuits for applications in ultrahigh-speed telecommunications, quantum information, on-chip spectroscopy, and non-destructive sensing, testing, and imaging. This paper reviews the history and recent advances in THz sources and detectors based on IJJs with a focus on the application of IJJ THz devices in THz spectroscopy, and various types of THz imaging systems such as r eflection, transmission, and computed tomography. We show that compact IJJ THz devices with sub-centimeter-sized modules are easy to use in many applications, as they can be regarded as pocket quantum THz torches.
Detection of Pulsed Terahertz Waves Using High-Temperature Superconductor Josephson Junction
Applied Physics Express, 2010
We report a novel terahertz (THz) detector with a high-T c superconducting (HTS) Josephson junction. This detector was fabricated using a YBa 2 Cu 3 O 7À grain boundary junction. Clear THz signals induced by THz-pulse radiation from an ultrafast photoconductive antenna excited by femtosecond optical pulses were observed. We investigated the characteristics of the detector by changing the parameters of THz radiation such as pump laser power for the THz emitter and THz polarization. The results indicate that the detector mainly detects the THz electric fields. This is the first demonstration of a detection of pulsed THz electric fields using an HTS Josephson junction.
Toward terahertz heterodyne detection with superconducting Josephson junctions
Applied Physics Letters, 2012
In this letter, we present the study of the high-frequency mixing properties of ion irradiated YBa2Cu3O7 Josephson nano-junctions. The frequency range, spanning above and below the characteristic frequencies fc of the junctions, permits a clear observation of the transition between two mixing regimes. The experimental conversion gain was found to be in good agreement with the prediction of the three ports model. Finally, we discuss the potential of the junctions to build a Josephson mixer operating in the terahertz frequency range.
THz Sources and Detectors Fabricated from High Temperature Superconductors
Terahertz (THz), Mid Infrared (MIR) and Near Infrared (NIR) Technologies for Protection of Critical Infrastructures Against Explosives and CBRN, 2021
High temperature superconductors have unique properties that can be useful in the THz region, single crystal constituted from superconducting CuO 2layers could sustain high voltages across the junctions and they are coupled through the intrinsic Josephson Effect this maintains the potential for very intense, coherent radiation which spreads over the THz gap. We investigated various experimental techniques to fabricate THz sources, bolometers and filters for efficient THz emission and detection. Rectangular mesa structures were fabricated on Bi 2 Sr 2 CaCu 2 O 8-x (Bi2212) single crystal superconductors using standard e-beam lithography and Ar ion beam etching systems and an emitted power as high as 60 μW at frequencies up to 0.85 THz was detected from micron sized continuous wave terahertz sources. We also fabricated bolometric microchips for THz detection purpose from Bi2212 single crystals. Bi2212 microchips detected the signals and response time were calculated, our results have clearly shown that Bi2212 single crystals are potential candidates for THz detection. The detection properties and sensitivity of bolometer chips can be further improved by integrating an antenna and filter structures. In order to investigate this we have fabricated metamaterial THz filters based on metals and YBa 2 Cu 3 O x superconducting thin films with metal-mesh shape and a unique fourcross shape pattern. Both a THz time domain spectrometer and a Fourier transform infrared spectrometer (FTIR) were used to investigate the performance
Journal of Physics: Conference Series, 2006
Detection of terahertz radiation using YBa 2 Cu 3 O 7-x [100]-tilt bicrystal junctions with high I c R n -product up to 6 mV has been studied. Two types of the responses ΔV (V) have been observed. At low frequencies up to some frequency f l , the responses ΔV (V) were proportional to the second derivative of the V(I)-curve. At high frequencies f > f l , the responses ΔV (V) demonstrate odd-symmetric resonances at V = hf/2e. For low-resistance junctions, Josephson frequency-selective detection was found up to the frequency of 5.3 THz, which is above the frequency of the strongest optical mode (f 0 = 4.6 THz) in YBa 2 Cu 3 O 7-x . The frequency f l was found to increase with the resistance R n and the I c R n -product of the junction. For high-resistance junctions with R n = 23 Ω, classical detection was observed up to 0.4 THz range. The difference in detection mechanisms is attributed to a continuous type of spectra of Josephson oscillations at low voltages and to a discrete type of Josephson spectra at high voltages. Computer simulation of a Josephson detector has been carried out, considering intensive thermal fluctuations and a frequency-dependent impedance of the Josephson junction. It is shown that a classical detector, based on the [100]-tilt Josephson junctions with R n =100 Ohm at T = 40 K, might reach the values of noise equivalent power NEP <2⋅ 10 -14 W/Hz 1/2 at the frequencies up to 1.8 THz.
Terahertz imaging using a high- T c superconducting Josephson junction detector
Superconductor Science and Technology, 2008
A high-T c superconducting (HTS) detector based on a YBa 2 Cu 3 O 7−x (YBCO) step-edge Josephson junction has been developed and applied to terahertz (THz) detection. The detector was coupled to a ring-slot antenna designed for operation at 600 GHz, and used for THz imaging. The results suggest that the characteristic voltage and frequency of our HTS step-edge junctions can be readily optimized for the chosen THz frequency range at easily achievable temperatures. The images also clearly demonstrate some of the unique properties of THz radiation, including the sensitivity to water content and the ability to penetrate packaging materials.
Terahertz detectors based on superconducting hot electron bolometers
Science China Information Sciences, 2011
Low noise terahertz (THz) heterodyne detectors based on superconducting niobium nitride (NbN) hot electron bolometers (HEBs) have been studied. The HEB consists of a planar antenna and an NbN bridge connecting across the antenna's inner terminals on a high-resistivity Si substrate. The double sideband noise temperatures at 4.2 K without corrections have been characterized from 0.65 to 3.1 THz. The excess quantum noise factor β of about 4 has been obtained, which agrees well with the calculated value. Allan variance of the HEB has been measured, and Allan time up to 20 s is obtained using a microwave feedback method. Also, the intermediate frequency gain bandwidth (GBW) was measured using two different methods, resulting in same GBW value of about 3.5 GHz. Keywords terahertz heterodyne detector, hot electron bolometer, noise temperature, stability, intermediate frequency gain bandwidth Citation Jiang Y, Jin B B, Xu W W, et al. Terahertz detectors based on superconducting hot electron bolometers. Sci China Inf Sci, 2012, 55: 64-71,