Theory and Simulation of Electromagnetic Wave Emission from Intrinsic Josephson Junctions

Tsujimoto

Yamamoto

et al. 2011

Jpn. J. Appl. Phys.

Coherent and continuous radiation sources of the electromagnetic (EM) waves at terahertz (1 THz = 10 12 c/s) frequencies using a mesa structure fabricated from high temperature superconducting Bi 2 Sr 2 CaCu 2 O 8þ single crystals are described with a special emphasis on the physics of the radiation mechanism and the applications. After the intensive studies of many mesas fabricated with different conditions, it is revealed that the ac-Josephson effect works as a primary driving mechanism of the radiation and the cavity resonance needed for stronger radiation plays an additional role to the mechanism, although both are working together while radiating. A prototype of the imaging machine for multipurpose uses has successfully been developed. #

Section: Historical Overviewmentioning

confidence: 99%

High Temperature Superconductor Terahertz Emitters: Fundamental Physics and Its Applications

Tsujimoto

Yamamoto

et al. 2011

Jpn. J. Appl. Phys.

“…After that pioneering study [10], several groups have studied IJJ-THz emitter devices constructed from a single crystal of Bi2212. The device characteristics have intensively been studied both theoretically [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] and experimentally . Recent progress of the IJJ-THz emitters was also reviewed [86,87].…”

Section: Introductionmentioning

confidence: 99%

The present status of high-T_csuperconducting terahertz emitters

Supercond. Sci. Technol.

Kubo

Sakamoto

et al. 2017

A terahertz (THz) wave emitter using the stack of intrinsic Josephson junctions present in the high-Tc superconductor Bi2Sr2CaCu2O8+δ (Bi2212) has been developed. By applying a dc voltage V across the stack, the ac-Josephson effect converts this to an ac-current that emits photons at the Josephson frequency proportional to V. The Bi2212 device also behaves as and electromagnetic (EM) cavity, so depending upon the shape of the Bi2212 crystal, when the Josephson frequency matches that of a cavity resonance, the emission power is enhanced. However, the EM radiation characteristics also strongly depend upon the effects of Joule self heating of the device. In order to alleviate this Joule heating problem, we fabricated three distinct stand-alone Bi2212 sandwich device shapes, each crystal being first covered with Au on its top and bottom, and then sandwiched between sapphire plates. From our comparative studies of the three devices, we obtained important clues that could help to increase the emission power up to ∼mW and the frequency range up to several THz, as necessary for many applications such as security screening, high speed communications, medical and biological sensing, and astronomical detection, etc.

“…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.…”

mentioning

confidence: 99%

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

Applied Physics Letters

Yamamoto

Kitamura

et al. 2015

To obtain higher power P and frequency f emissions from the intrinsic Josephson junctions in a high-Tc superconducting Bi2Sr2CaCu2O8+δ single crystal, we embedded a rectangular stand-alone mesa of that material in a sandwich structure to allow for efficient heat exhaust. By varying the current-voltage (I-V) bias conditions and the bath temperature Tb, f is tunable from 0.3 to 1.6 THz. The maximum P of a few tens of μW, an order of magnitude greater than from previous devices, was found at Tb∼55 K on an inner I-V branch at the TM(1,0) cavity resonance mode frequency. The highest f of 1.6 THz was found at Tb=10 K on an inner I–V branch, but away from cavity resonance frequencies. A possible explanation is presented.