Terahertz emission from mutually synchronized standalone Bi2Sr2CaCu2O8+x intrinsic-Josephson-junction stacks

Fuente: arXiv
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Main Authors: Wieland, Raphael, Kizilaslan, Olcay, Kinev, Nickolay, Dorsch, Eric, Guénon, Stefan, Song, Ziyu, Wei, Zihan, Wang, Huabing, Wu, Peiheng, Koelle, Dieter, Koshelets, Valery P., Kleiner, Reinhold
Format: Preprint
Published: 2024
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author Wieland, Raphael
Kizilaslan, Olcay
Kinev, Nickolay
Dorsch, Eric
Guénon, Stefan
Song, Ziyu
Wei, Zihan
Wang, Huabing
Wu, Peiheng
Koelle, Dieter
Koshelets, Valery P.
Kleiner, Reinhold
author_facet Wieland, Raphael
Kizilaslan, Olcay
Kinev, Nickolay
Dorsch, Eric
Guénon, Stefan
Song, Ziyu
Wei, Zihan
Wang, Huabing
Wu, Peiheng
Koelle, Dieter
Koshelets, Valery P.
Kleiner, Reinhold
contents Suitably patterned single crystals made of the cuprate superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ (BSCCO), intrinsically forming a stack of Josephson junctions, can generate electromagnetic radiation in the lower terahertz regime. Due to Joule heating the emission power of single stacks seems to be limited to values below 100 $μ$W. To increase the radiation power, mutually synchronized arrays situated on the same BSCCO base crystal have been studied. Mutual electromagnetic interactions via a connecting BSCCO base crystal have been considered essential for synchronization, but the approach still suffers from Joule heating, preventing the synchronization of more than three stacks. In the present paper we show, on the basis of two emitting stacks, that mutual synchronization can also be achieved by stand-alone stacks contacted by gold layers and sharing only a common gold layer. Compared to BSCCO base crystals, the gold layers have a much higher thermal conductivity and their patterning is not very problematic. We analyze our results in detail, showing that the two oscillators exhibit phase correlations over a range of $\pm$0.4 GHz relative to their center frequencies, which we mainly studied between 745 GHz and 765 GHz. However, we also find that strong phase gradients in the beams radiated from both the mutually locked stacks and the unlocked ones play an important role and, presumably, diminish the detected emission power due to destructive interference. We speculate that the effect arises from higher-order cavity modes which are excited in the individual stacks. Our main message is that the mutual interaction provided by a common gold layer may open new possibilities for relaxing the Joule-heating-problem, allowing the synchronization of a higher number of stacks. Our findings may boost attempts to substantially increase the output power levels of the BSCCO terahertz oscillators.
format Preprint
id arxiv_https___arxiv_org_abs_2405_20742
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Terahertz emission from mutually synchronized standalone Bi2Sr2CaCu2O8+x intrinsic-Josephson-junction stacks
Wieland, Raphael
Kizilaslan, Olcay
Kinev, Nickolay
Dorsch, Eric
Guénon, Stefan
Song, Ziyu
Wei, Zihan
Wang, Huabing
Wu, Peiheng
Koelle, Dieter
Koshelets, Valery P.
Kleiner, Reinhold
Superconductivity
Suitably patterned single crystals made of the cuprate superconductor Bi$_2$Sr$_2$CaCu$_2$O$_{8+x}$ (BSCCO), intrinsically forming a stack of Josephson junctions, can generate electromagnetic radiation in the lower terahertz regime. Due to Joule heating the emission power of single stacks seems to be limited to values below 100 $μ$W. To increase the radiation power, mutually synchronized arrays situated on the same BSCCO base crystal have been studied. Mutual electromagnetic interactions via a connecting BSCCO base crystal have been considered essential for synchronization, but the approach still suffers from Joule heating, preventing the synchronization of more than three stacks. In the present paper we show, on the basis of two emitting stacks, that mutual synchronization can also be achieved by stand-alone stacks contacted by gold layers and sharing only a common gold layer. Compared to BSCCO base crystals, the gold layers have a much higher thermal conductivity and their patterning is not very problematic. We analyze our results in detail, showing that the two oscillators exhibit phase correlations over a range of $\pm$0.4 GHz relative to their center frequencies, which we mainly studied between 745 GHz and 765 GHz. However, we also find that strong phase gradients in the beams radiated from both the mutually locked stacks and the unlocked ones play an important role and, presumably, diminish the detected emission power due to destructive interference. We speculate that the effect arises from higher-order cavity modes which are excited in the individual stacks. Our main message is that the mutual interaction provided by a common gold layer may open new possibilities for relaxing the Joule-heating-problem, allowing the synchronization of a higher number of stacks. Our findings may boost attempts to substantially increase the output power levels of the BSCCO terahertz oscillators.
title Terahertz emission from mutually synchronized standalone Bi2Sr2CaCu2O8+x intrinsic-Josephson-junction stacks
topic Superconductivity
url https://arxiv.org/abs/2405.20742