Quantum terahertz electronics (QTE) using coherent radiation from high temperature superconducting Bi2Sr2CaCu2O8+δ intrinsic Josephson junctions

Generation of electromagnetic waves from 0.3 to 1.6 terahertz with a high-Tc superconducting Bi2Sr2CaCu2O8+δ intrinsic Josephson junction emitter

“…The intrinsic Josephson junction (IJJ) terahertz (THz) emitter (IJJ-THz emitter) based on the IJJs present in the high-T c superconductor Bi 2 Sr 2 CaCu 2 O 8þd (Bi2212) [1][2][3] has been developed experimentally and theoretically. [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] So far, its demonstrated radiation characteristics are the f range from 0.3 to 1.0 THz, 4,22,23 the maximum P of $30 lW, [19][20][21][22] and coherent, continuous-wave emission with a spectral width of less than 0.5 GHz. 12,13 Recently, by synchronizing the emissions from a three-mesa array, P $ 610 lW was reported.…”

“…The observed emission P from stand-alone mesas was at least one order of magnitude higher than from mesas with Bi2212 substrates. 19,21,22 Here, we describe a simple device structure based on the stand-alone mesa that is easy to fabricate, assemble, and operate, and produces highly reproducible high-power emission that is tunable from 0.3 to 1.6 THz.…”

“…53,54 We first annealed a piece of a Bi2212 single crystal overnight to obtain an appropriate doping level. [10][11][12][20][21][22] After freshly cleaving both surfaces of a piece of the annealed Bi2212 single crystal, making it a few lm thick, both surfaces were coated with silver and gold by evaporation.…”

“…Accounting for the rectangular mesa radiation pattern and the losses at the detector and from all materials between the mesa and the detector, the total radiation power was estimated to be on the order of a few tens of lW, comparable to the maximum power observed from previous stand-alone mesas. 19,21,22 In Fig. 2(b), f is plotted versus the bias V at the colorcoded T b values.…”

“…The radiation intensity spectrum has distinct peaks at around 0.55 THz and 1.1 THz, which fall within the respective TM(1,0) and T(2,0) cavity resonance mode frequency ranges (0.62 $ 0.54 THz and 1.2 $ 1.1 THz) of the rectangular mesa of width range 58-66 lm and index of refraction n $ 4.2. [10][11][12][20][21][22] This strongly suggests that both of these cavity resonance modes are enhancing the output P. These two modes were also seen in Fig. 2(a), where the TM(1,0) mode is excited at around 2.2 V at 50 K, and the TM(2,0) mode is excited at 6 V at 15 K. The P observed at the lower TM(1,0) mode frequency and higher T b values is an order of magnitude stronger than that observed at the higher TM(2,0) mode frequency and lower T b values.…”