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SUMMARY:Overcoming the Terahertz Gap Using High-Tc Superconductor Bi2Sr2Ca
 Cu2O8+Mesa Devices as Emitters - Professor Kazuo Kadowaki\; Universi
 ty of Tsukuba\, Japan
DTSTART:20160408T131500Z
DTEND:20160408T141500Z
UID:TALK65444@talks.cam.ac.uk
CONTACT:Teri Bartlett
DESCRIPTION:Electromagnetic Waves at terahertz (THz) frequencies are indis
 pensable not only for the basic research but also a variety of application
 s such as environmental sensing\, imaging\, molecular identification\, dra
 g and explosive detection\, pharmaceutical screening\, biological and medi
 cal use\, ultrafast communications\, etc. However\, such applications at T
 Hz frequencies have been far from reality for a long time because a sharp 
 gap in the frequency-power diagram centered around 1 THz\, known as the 
 “Terahertz gap”\, could not be overcome in the history of electromagne
 tic wave generation.\n\nIn 2007\, the discovery of the coherent and contin
 uous electromagnetic waves in the THz region from a large mesa structure m
 ade of high-Tc superconductor Bi2Sr2CaCu2O8+d by Ozyuzer et al. [1] shed a
  dim light on the issue of the terahertz gap. Since then\, much effort has
  been concentrated not only on the basic understanding of the mechanism of
  THz emission from ～10^3 intrinsic Josephson junctions existing in the m
 esa but also on the development of higher power and higher frequency THz g
 eneration. We have just recently succeeded in generating a maximum frequen
 cy of 2.4 THz [2] and the power of 50 microwatt/mesa\, and in operating at
  liquid nitrogen temperature [3].\n\nI will give a short history of IJJ TH
 z emitter development [4\,5]\, then\, the present status [6\,7] and the fu
 ture perspectives of the IJJ emitter\, especially in comparison with the s
 imilar semiconducting devices such as resonant-tunneling diodes (RTDs) and
  quantum cascade lasers (QCLs) etc.\n\nReferences\n[1]. L. Ozyuzer et al.\
 , Science 318 (2007) 1291.\n[2]. T. Kashiwagi et al.\, Appl. Phys. Lett. 1
 07 (2015) 082601.\n[3]. H. Minami et al.\, J. Phys.: Condens. Matter 28 (2
 016) 025701.\n[4]. U. Welp\, K. Kadowaki and R. Kleiner\, Nature Photon. 7
  (2013) 702.\n[5]. T. Kashiwagi et al.\, Phys. Rev. Applied 4 (2015) 05401
 8.\n[6]. K. Nakade et al.\, Scientific Reports 6 (2016) 23178.\n[7]. K. De
 lfanazari et al.\, IEEE Trans. Terahertz Sci. & Technol. 5 (2015) 505.\n
LOCATION:Small Lecture Theatre\, Bragg Building\, Room 133\, Cavendish Lab
 oratory\, Department of Physics
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