Study of Radiation Characteristics of Intrinsic Josephson Junction Terahertz Emitters with Different Thickness of Bi2Sr2CaCu2O8+δ Crystals

Abstract

The radiation intensity from the intrinsic Josephson junction high-Tc superconductor Bi2Sr2CaCu2O8+δ terahertz emitters (Bi2212-THz emitters) is one of the most important characteristics for application uses of the device. In principle, it would be expected to be improved with increasing the number of intrinsic Josephson junctions N in the emitters. In order to further improve the device characteristics, we have developed a stand alone type of mesa structures (SAMs) of Bi2212 crystals. Here, we understood the radiation characteristics of our SAMs more deeply, after we studied the radiation characteristics from three SAMs (S1, S2, and S3) with different thicknesses. Comparing radiation characteristics of the SAMs in which the number of intrinsic Josephson junctions are N∼ 1300 (S1), 2300 (S2), and 3100 (S3), respectively, the radiation intensity, frequency as well as the characteristics of the device working bath temperature are well understood. The strongest radiation of the order of few tens of microwatt was observed from the thickest SAM of S3. We discussed this feature through the N2-relationship and the radiation efficiency of a patch antenna. The thinner SAM of S1 can generate higher radiation frequencies than the thicker one of S3 due to the difference of the applied voltage per junctions limited by the heat-removal performance of the device structures. The observed features in this study are worthwhile designing Bi2212-THz emitters with better emission characteristics for many applications.

Millimeter-Waves to Terahertz SISO and MIMO Continuous Variable Quantum Key Distribution

“…As shown in Fig. 1 (b), the whole model of a MIMO system could be described by [71,72] 𝒂 ̂𝐵 = 𝑼 † 𝑯𝑽𝒂 ̂𝐴 + 𝑼 † 𝑼𝑺𝒂 ̂𝐸 (20) where 𝒂 ̂𝐵 = [𝑎 ̂𝐵,1 , … , 𝑎 ̂𝐵,𝑁 𝑟 ] 𝑇 is the received mode of Bob, 𝒂 ̂𝐴 = [𝑎 ̂𝐴,1 , … , 𝑎 ̂𝐴,𝑁 𝑡 ] 𝑇 is the transmitted mode of Alice, 𝒂 ̂𝐸 = [𝑎 ̂𝐸,1 , … , 𝑎 ̂𝐸,𝑁 𝑡 ] 𝑇 is the injected Gaussian mode of Eve. 21) is a diagonal matrix with 𝑀 = min(𝑁 𝑡 , 𝑁 𝑟 ).…”

“…A gap in the electromagnetic spectrum exists at these frequency ranges due to the inefficient and unpractical of the devices and circuits [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. However, the recent development of electronic, photonic and plasmonic-based mm-waves and THz technologies help close this gap with the demonstration of power-efficient sources [20][21][22][23][24][25][26], antennas [27][28][29][30][31], filters [32][33][34], waveguides [29,[35][36][37][38][39], modulators [40][41][42][43][44][45][46][47][48]…”

Engineering ultrastrong coupling between Josephson plasmon polaritons and subwavelength microcavity arrays in silicon/van der Waals layered superconductor heterostructure for terahertz hybrid circuit cavity quantum electrodynamics

“…In the category of HTS, Bi2Sr2CaCu2O8+δ (BSCCO) based devices have shown a potential to close the THz gap [7][8][9][10][11]. The crystal of HTS BSCCO is a stack of two-dimensional (2D) layers composed of alternating layers of superconducting copper oxides (CuO2) and non-superconducting bismuth/strontium oxides (Bi2O2 and SrO) forming intrinsic Josephson junctions (IJJs) or Josephson medium [12][13][14][15]. Therefore, superconductivity in BSCCO is confined to 2D planes [16] and the relatively weak van der Waals (vdWs) forces between the layers keep the stack together [17].…”

Emission from Josephson junctions with Gaussian distribution of critical currents

“…One can also calculate such a spectrum for the model system and compare it with the experiment. Such calculations become actual recently because of investigations of the coherent emission from high-temperature superconductors which reveal the intrinsic Josephson effect [1][2][3]. Strong coherent emission without applied magnetic field was observed at resonant steps of IV-characteristic of mesa-structures made of these superconductors.…”