On-chip diagnostic of high-Tc superconductors at mm-wave frequencies (original) (raw)
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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.
Physica C-superconductivity and Its Applications, 2002
The submillimeter wave signal detection has been experimentally studied for a high-Tc superconducting device, consisting of a bicrystal YBa2Cu3Ox Josephson junction, incorporated with a log-periodic antenna. Measurements were carried out in wide range of temperatures T=20–80 K. At relatively high temperatures T>60 K, the thermally activated phase slippage began to predominate. At the same time, a set of clearly resolved detector response functions have been registered up to the temperatures close to the critical one. At the highest temperature T≃80 K, where detector response has been registered, the ratio of the frequency of applied signal fs≃500 GHz to the critical frequency of Josephson junction fc has been estimated as large as fs/fc≃40.
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.
High sensitivity high Tc superconducting Josephson junction antenna for 200 GHz detection
Journal of Electromagnetic Waves and Applications, 2018
A high sensitivity rounded bow-tie antenna was optimized based on electromagnetic simulations. The bicrystal Josephson junction detector with a thin layer of YBCO was located exactly at the bicrystal misorientation point at the center of the antenna. The Au antenna was fabricated on an (100) MgO bicrystal substrate. In the presence of 200 GHz RF radiation, a noise equivalent power (NEP) of around 6×10 −12 W Hz −1/2 was measured, with a voltage sensitivity, η(V), of 30 dB with the detector at 60 K. Even though no coupling lens was used, these results are as good as those reported in systems in which the impinging radiation was focused with lenses over the detectors. Thus, important simplification of the system was obtained without loss of sensitivity.
Application of High-Tc Superconducting Josephson Junction Devices
2019
Abstract: The application of superconducting devices based on Josephson junction has been investigated for many years. Josephson junction is based on quantum mechanical tunneling of electrons between weakly coupled two superconducting regions. Its unique properties make it a building block for future superconducting electronic circuits. In this paper, attempt has been made to highlight the wide range of application of Josephson junction including Josephson voltage standard, SQUIDs, Quantum Computer, analog to digital converter, RSFQ digital electronics, terahertz emitter and detector etc.
Microwave Characterization of Josephson Junction Arrays: Implementing a Low Loss Superinductance
Physical Review Letters, 2012
We have measured the plasma resonances of an array of Josephson junctions in the regime EJ EC , up to the ninth harmonic by incorporating it as part of a resonator capacitively coupled to a coplanar waveguide. From the characteristics of the resonances, we infer the successful implementation of a superinductance, an electrical element with a non-dissipative impedance greater than the resistance quantum (RQ = h/(2e) 2 6.5 kΩ) at microwave frequencies. Such an element is crucial for preserving the quantum coherence in circuits exploiting large fluctuations of the superconducting phase. Our results show internal losses less than 20 ppm, self-resonant frequencies greater than 10 GHz, and phase slip rates less than 1 mHz, enabling direct application of such arrays for quantum information and metrology. Arrays with a loop geometry also demonstrate a new manifestation of flux quantization in a dispersive analog of the Little-Parks effect.
Bandwidth and noise of submillimeter wave cuprate bicrystal Josephson junction detectors
IEEE Transactions on Applied Superconductivity, 2005
Detectors made from superconducting cuprate YBa 2 Cu 3 Ox bicrystal Josephson junctions (BJJs) on sapphire and NdGaO 3 substrates have been fabricated and characterized in the frequency band 200-900 GHz. Junctions on sapphire substrates had a normal state resistance 15 60 , and product up to 2.5 mV at = 4 2 K. Junctions on NdGaO 3 substrates had lower = 1 5 and = 0 4-0.9 mV at = 77 K. Three types of detecting devices have been investigated in both the broadband and the frequency-selective detection modes. One type was patterned with log-periodic antenna, and two others with Pt-metal double-slot antenna designed for a central frequency = 300 GHz and = 400 GHz, respectively. Measurements at = 320 GHz of the reception bandwidth 1f for a device with double-slot antenna gave a quality factor = 1 10. A low-noise cooled 1-2 GHz bandwidth amplifier enables a better sensitivity in the self-pumping frequency mixing mode, avoiding the 1/f noise. The dependence of the spectral density of noise on voltage was compared to the data for the Josephson emission linewidth obtained by the selective detector response method. Also discussed are measurements at 500 GHz of the NEP values carried out at different experimental conditions. Index Terms-High-temperature cuprate superconductors, Josephson junction, submillimeter wave devices.
High-Tc superconducting Josephson mixers for terahertz heterodyne detection
Journal of Applied Physics, 2014
We report on an experimental and theoretical study of the high-frequency mixing properties of ion-irradiated YBa2Cu3O7 Josephson junctions embedded in THz antennas. We investigated the influence of the local oscillator power and frequency on the device performances. The experimental data are compared with theoretical predictions of the general three-port model for mixers in which the junction is described by the resistively shunted junction model. A good agreement is obtained for the conversion efficiency in different frequency ranges, spanning above and below the characteristic frequencies fc of the junctions.
High-Tc superconducting detector for highly-sensitive microwave magnetometry
Applied Physics Letters
We have fabricated arrays of High-T c Superconducting Quantum Interference Devices (SQUIDs) with randomly distributed loop sizes as sensitive detectors for Radio Frequency (RF) waves. These subwavelength size devices known as Superconducting Quantum Interference Filters (SQIFs) detect the magnetic component of the electromagnetic field. We used a scalable ion irradiation technique to pattern the circuits and engineer the Josephson junctions needed to make SQUIDs. Here, we report on a 300 SQUID series array with the loop area ranging from 6 to 60 lm 2 , folded in a meander line covering a 3.5 mm  120 lm substrate area, made out of a 150 nm thick YBa 2 Cu 3 O 7 film. Operating at a temperature of T ¼ 66 K in an unshielded magnetic environment under low DC bias current (I ¼ 60 lA) and a DC magnetic field (B ¼ 3 lT), this SQIF can detect a magnetic field of a few picoteslas at a frequency of 1.125 GHz, which corresponds to a sensitivity of a few hundreds of fT= ffiffiffiffiffiffi Hz p and shows a linear response over 7 decades in RF power. This work is a promising approach for the realization of low dissipative subwavelength gigahertz magnetometers.