Continuous 30 μW terahertz source by a high-Tc superconductor mesa structure

Abstract

Using a modified mesa structure of high-T c superconducting Bi 2 Sr 2 CaCu 2 O 8þd with a thin underlaying base superconductor ($3 lm), the effective working temperature of the continuous and monochromatic terahertz emitter is extended up to 70 K, and the maximum power of $30 lW at 0.44 THz is achieved at the relatively high temperature of T b ¼ 55 K in a low bias current retrapping region. The diverging behavior of the intensity occurring at 55 K in the low current regime without hot spot formation may provide us an important clue for the stronger THz radiation from intrinsic Josephson junction devices. V

Three-Dimensional Simulations of the Electrothermal and Terahertz Emission Properties ofBi2Sr2CaCu2Rudau1, Wieland2, Langer3 et al. 2016Phys. Rev. Applied300270View full textAdd to dashboardCite

“…Emission frequencies range from 0.3 to 2.4 THz. For the best stacks, an emission power P e in the range of tens of µW has been achieved 17,19,20,32,33 , and arrays of mesas showed emission with P e up to 0.61 mW 19 . The physics of the huge IJJ stacks is affected by Joule heating 1, 3,5,6,8,13,18,22,26,30,49,52,54,55,63 .…”

“…For example, it has been found that the linewidth of radiation is much narrower in the high-bias regime than at low bias 12,60 . Other properties such as the emission frequency seem to be basically independent of the hot spot position, leading to some debate as to whether the hot spot is helpful for radiation or just coexists with the radiating regions 20,22,23 . In fact, recent results showed that there is a strong interaction 28 .…”

“…IJJ stacks, containing 500 -2000 junctions, have been patterned as mesas but also as bare IJJ stacks contacted by Au layers (GBG structures) 16,17,20,24 and as all-superconducting structures 11 . Emission frequencies range from 0.3 to 2.4 THz.…”

Excess of topological defects induced by confinement in vortex nanocrystals

“…The growing demand of miniaturization in superconducting devices applied to the detection of different types of radiation [1][2][3][4][5] and magnetic signals [6][7][8] has triggered the study of thermodynamic and transport properties of high-T c superconducting materials at the micro and nanoscale. Since many of these devices operate in the mixed state, understanding the change in thermodynamic and structural properties of vortex matter when reducing the number of vortices down to the nanoscale is crucial for predicting their working-range.…”

Control of circularly polarized THz wave from intrinsic Josephson junctions by local heating

“…Stacks of these natural Josephson junctions, which are referred to as intrinsic Josephson junctions (IJJs), can generate an AC Josephson current in the THz frequency range by application of a voltage, and the THz wave emission is attributed to the generation of this current. Intense THz emissions have been reported for IJJs fabricated in a mesa geometry, which itself behaves as a cavity resonator, and thus, a number of studies on such IJJ mesas have been carried out both experimentally [4][5][6][7][8][9][10][11][12][13][14][15] and theoretically [16][17][18][19][20][21][22][23][24][25][26]. However, in the previous studies, little attention was given to the state of the polarization of the THz waves.…”