Terahertz emission from the intrinsic Josephson junctions of high-symmetry thermally-managed Bi₂Sr₂CaCu₂O_8+δmicrostrip antennas

Compact High- Tc Superconducting Terahertz emitter operating up to 86 K

“…For bath temperatures between 27.8 and 86 K, as plotted in Fig. 4(a), emission is observed over a frequency range from 0.37 to 2.09 THz, with two prominent [63,64], and it was shown that, apart from resonances oscillating with k half waves along the length of the stack and l half waves along its width, because of degeneracy of resonant modes of the square geometry, there can be a number of mixed modes. Indeed, the emission peaks observed near 0.5 THz in Fig.…”

“…Coherent off-chip * hbwang@nju.edu.cn terahertz emission was first demonstrated for 1-μm-thick BSCCO stacks, with an extrapolated output power of up to 0.5 μW for emission frequencies f e between 0.5 and 0.85 THz [6], and it has been proposed that resonant modes utilizing the stack as a cavity and oscillating along the width of the stack play an important role for synchronization. A variety of cavity resonances have indeed been found and analyzed [7][8][9]11,13,14,47,[62][63][64]. For the best stacks the detected terahertz power is now on the order of tens of microwatts [22,23,27,70], with a maximum value of 610 μW achieved by a synchronized three-mesa array [22].…”

Improved excitation mode selectivity of high-Tc superconducting terahertz emitters

“…Nevertheless, it is possible to further analyze the possible cavity mode excitations by including the full symmetry of the rectangular point group C 2v . For a thin rectangular device structure of width w and length ', the normalized TM wave functions W n;m ðx; yÞ for the magnetic vector potential A z (and the electric field E z ) of the cavity modes satisfying the Neumann boundary conditions (with vanishing normal derivatives on each of the boundaries 85,86 ) may be written as W n;m ðx; yÞ ¼ 2 ffiffiffiffiffi ffi w' p cos ðnpx=wÞ cos ðmpy='Þ;…”

“…where for simplicity we take the lower left and upper right corners of the rectangle to be, respectively, at the origin and at the point ðw; 'Þ. For a rectangular microstrip antenna, all of the TM n,m modes are one-dimensional representations of the C 2v point group, 86 and therefore have fixed nodal line positions during the amplification process of a resonance. 76,85,86 The frequencies f c n;m of the resonant cavity modes are then easily found to be 86…”

“…The IJJ-THz emitters based upon superconducting Bi2212 single crystals have intensively been developed both experimentally and theoretically. [67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86] So far, the best performance has been achieved within the frequency range from 0.3 to 11 THz, [11][12][13]34,35,39 with the maximum output power of $30 lW, [31][32][33][34]39 and with a spectral width of the coherent and continuous emission of THz radiation that is generally less than 0.5 GHz, and under appropriate conditions, it was reported to be narrower than 23 MHz and possibly even 6 MHz. [23][24][25] Furthermore, a synchronized operation of an array of three such emitters was reported to yield the greatly enhanced power of 610 lW.…”