Thermal Tuning of High-Tc Superconducting Bi2Sr 2CaCu2 O8+δ Terahertz Metamaterial

Impact Statement:We report on the first demonstration of a low loss and tunable metamaterial based on high-temperature superconducting BSCCO. BSCCO with large superconducting energy gap is the building block of a compact, powerful, continuous and coherent THz source which has been found promising to close the THz gap. Our proposed metamaterial can be integrated with BSSCO THz emitters to improve their functionalities.Abstract:We introduce a class of low-loss subwavelength resonators and report the first demonstration of a high-temperature ( Tc) superconducting Bi 2Sr2 CaCu2O 8+δ (BSCCO) terahertz (THz) metamaterial. The numerical simulations and analytical calculations are performed to study the electromagnetic response of the subwavelength BSCCO split-ring resonators (SRRs) to the incident photons with energies below the superconducting gap energy. A transition of resonance strength is observed as a dip in resonance frequency for temperatures below BSCCO Tc. To interpret the transmission spectra, resonance switching, and frequency tuning of SRRs, we calculate the temperature dependent complex permittivity and surface impedance of a 200 nm thick unpatterned slightly underdoped BSCCO thin film. We compare the resonance tunability of SRRs made of the extremely disorder superconductor (BSCCO) with metamaterials made of a weakly disorder superconductor YBa2Cu3O7 (YBCO) and show that the resonance quality and frequency tuning are comparable for these two metamaterials. Our results may be useful for THz emitters and detectors developments, for instance, by integration of SRRs with BSCCO THz emitters and microstrip antennas, the device functionalities such as polarization, emission pattern directivity, and output power could be controlled and improved

Thermal tuning of high-Tc superconducting Bi2Sr 2CaCu2 O8+δ terahertz metamaterial

We introduce a class of low-loss subwavelength resonators and report the first demonstration of a high-temperature ( Tc ) superconducting Bi 2 Sr 2 CaCu 2 O 8+δ (BSCCO) terahertz (THz) metamaterial. The numerical simulations and analytical calculations are performed to study the electromagnetic response of the subwavelength BSCCO split-ring resonators (SRRs) to the incident photons with energies below the superconducting gap energy. A transition of resonance strength is observed as a dip in resonance frequency for temperatures below BSCCO Tc . To interpret the transmission spectra, resonance switching, and frequency tuning of SRRs, we calculate the temperature dependent complex permittivity and surface impedance of a 200 nm thick unpatterned slightly underdoped BSCCO thin film. We compare the resonance tunability of SRRs made of the extremely disorder superconductor (BSCCO) with metamaterials made of a weakly disorder superconductor YBa 2 Cu 3 O 7 (YBCO) and show that the resonance quality and frequency tuning are comparable for these two metamaterials. Our results may be useful for THz emitters and detectors developments, for instance, by integration of SRRs with BSCCO THz emitters and microstrip antennas, the device functionalities such as polarization, emission pattern directivity, and output power could be controlled and improved

Guiding of terahertz photons in superconducting nano-circuits

The field of plasmonics, as one of the fascinating areas of photonics, has received great attention for its capability of deep subwavelength confinement. We present a nanoscale plasmonic slot waveguide based on high transition temperature (T{c}) superconductor Bi{2}Sr{2}CaCu{2}{O}{8+\delta},(BSCCO). The effect of geometrical parameters on the modal properties of the BSCCO plasmonic slot waveguide and the thermal tuning of the modal properties of the waveguide are explored. It is shown that the rising of temperature results in increasing the mode effective refractive index in exchange for decreasing the propagation length of surface plasmon polaritons (SPPs). Our proposed plasmonic waveguide paves the way for the development of the BSCCO based THz photonic integrated circuity at the nanoscale

On-chip Superconducting THz Metamaterial Bandpass Filter

We demonstrate a THz bandpass filter (BPF) made from high-temperature (Tc) superconducting BiSrCaCuO+δ(BSCCO). The filter offers a thermally tunable dual passband with a flat response in the first passband, a bandwidth of \sim 0.33 THz, and a sharp resonance band-edge transition to the rejection bands of \sim 316 and 96 dB/THz (for left and right edge, respectively), at temperature T=10 K far below T_{\mathrm{c}}. As temperature T increases, the sharpness of the band-edge transition to the rejection bands decreases. The proposed BPF can be useful in the realization of a superconducting based THz integrated circuitry

On-chip Superconducting THz Metamaterial Bandpass Filter

We demonstrate a THz bandpass filter (BPF) made from high-temperature (T c ) superconducting Bi 2 Sr 2 CaCu 2 O 8+ δ (BSCCO). The filter offers a thermally tunable dual passband with a flat response in the first passband, a bandwidth of ∼0.33 THz, and a sharp resonance band-edge transition to the rejection bands of ∼316 and 96 dB/THz (for left and right edge, respectively), at temperature T=10 K far below Tc . As temperature T increases, the sharpness of the band-edge transition to the rejection bands decreases. The proposed BPF can be useful in the realization of a superconducting based THz integrated circuitry

Magnetoimpedance and magnetooptical properties of electrodeposited NiFeMo ribbons

We produced NiFeMo ribbons by electrodeposition technique under applied currents ranging from 40 to 240 mA. The SEM analysis showed a uniform and crack-free coating. Then, we measured the transverse and longitudinal magnetoimpedance of ribbons. We also obtained the hysteresis loops of the ribbons by means of magnetooptical Kerr effect to investigate their magnetic properties. The result showed that the increase in deposition current density caused a decline in the magnetic softness of the ribbons so that some of the ribbons exhibited an exchange spring effect. The magnetic hardening also caused a reduction in the magnetoimpedance response. We also theoretically calculated the susceptibility of a ribbon by considering the random magnetic anisotropy. The multi-peak behavior of susceptibility is in agreement with the multi-peak behavior of magnetoimpedance

Skin-effect-mediated magnetoionic control of charge transport in thick layers

Abstract In the rapidly developing area of magnetoionics (MI), which combines electrochemistry and magnetism, changes in the surface chemistry of magnetic materials in response to gate voltages cause dramatic modifications in the magnetic characteristics, resulting in low power-consuming charge transport tuning. Due to the surficial character, only magnetic thin films have been addressed for the MI effect’s role in controlling charge transfer. Here, we show how it can be used to regulate the transit of charges in bulk magnetic materials. This is accomplished by combining high-permeability magnetic materials with a high-frequency passing current, allowing the skin effect and the MI effect to control the magnetic materials’ impedance due to the impedance’s high sensitivity to magnetic permeability. Our in-situ impedance measurement and magneto-optical characterization show the role of redox reactions at the surface in controlling impedance in magnetic materials. This research paves the way for using the MI effect in high-permeability bulk magnetic materials