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Coherent THz Radiation from Intrinsic Josephson Junctions. K. Kadowaki , M. Tsujimoto, K. Yamaki, N. Orita, T. Koike, T. Kashiwagi, H. Minami, T. Yamamoto, T. Hattori, Krsto Ivanovic, M. Tachiki Institute of Materials Science, and Graduate School of Pure and Applied Sciences,
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Coherent THz Radiation from Intrinsic Josephson Junctions K. Kadowaki, M. Tsujimoto, K. Yamaki, N. Orita, T. Koike, T. Kashiwagi, H. Minami, T. Yamamoto, T. Hattori, Krsto Ivanovic, M. Tachiki Institute of Materials Science, and Graduate School of Pure and Applied Sciences, University of Tsukuba A. E. Koshelev, K. E. Gray, W. –K. Kwok and U. Welp Materials Science Division, Argonne National Laboratory and Richard Klemm Department of Physics, University of Central Florida http://kadowaki.ims.tsukuba.ac.jp/, http://www.tsukuba.ac.jp Lecture given at the Institute of Radio-Engineering and Electronics, Russian Academy of Sciences, Moscow, Russia, July 19th, 2010.
Outline of Talk Issues to be discussed (1). Brief Introduction THz waves: What is special ? (2). Josephson Plasma Excitation (3). THz Radiation Electromagnetic Mode Determination • Shape dependence • Rectangular, cylindrical, square mesas • Angular dependence • Mechanism of Radiation (4). Excitations from Individual Layers (3). More Experimental Results coherent operation of two junctions
kiro mega giga peta zetta tera yotta exa 106 103 1018 109 1024 100 1015 1021 1012 FREQUENCY (Hz) x-ray g-ray MF VHF SHF HF UHF EHF microwave Photonics Electronics THz FIR NIR visible MIR 1011 1010 1012 1013 1014 frequency 10[GHz] 100[GHz] 1 [THz] 10[THz] 100 [THz] wave length 3[cm] 3[mm] 300[mm] 30[mm] 3[mm] wave number 0.33[cm-1] 3.3[cm-1] 33[cm-1] 330[cm-1] 3300[cm-1] Atomic spectroscopy Molecular Spectroscopy Macromolecule fundamental mode electronic transition rotational mode higher harmonics
Characteristics of THz from IJJ’s Advantages 1. New generation mechanism: using collective modes in superconductors (Josephson plasma modes, not quantized energy levels) 2. Vibrationaland rotational modes of molecules, bio-molecular substances such as DNA, RNA, etc.: applied all kinds of materials 3. Chemical finger prints: distinction of materials from atomic or molecular levels in drug industries for separation, detection, etc. 4. Low energy: 1 THz = 4 meV = 50 K 5. Nondestructive and noninvasive: non-ionizing, but thermal effects 6. Compact and all solid state devices: small, light, high power efficiency 7. Imaging purposes: medical use, security issues, defense, food industries, quality control, etc. 8. Communication:high speed communications at near distances Disadvantages 1. Necessary to cool below Tc=80 K
Bi-2212 order parameter y CuO2 CuO2 Schematic view of rectangular mesa 1.53 nm SrO Ozyuzer et al., Science, 318 1291 (2007) Bi2O2 SrO |y|2 CuO2 CuO2 SrO Bi2O2 SrO CuO2 CuO2 Intrinsic inhomogeneity Bi2Sr2CaCu2O8+dIntrinsic Josephson Junctions unit cell of Bi2212 multilayer effects • R. Kleiner et al., Phys. Rev. Lett. B49 (1992) 23940 • G. Oya, et al., Jpn. J. Appl. Phys. 31 (1992) L829.. • K. Kadowaki & T. Mochiku, PhysicaB195-196 (1994) 2239. 1 mm=760 layers
Gc/s Josephson plasma j Single junction Multi-junctions A microwave • P. W. Anderson, “Lectures on The Many-Body Problem” (vol. II), edited by E. R. Caianiello, Academic press, 1964, p113. • B. D. Josephson, “Quantum Fluids, Proc. Susex Univ. Symp.”, 16-20, 1965, ed by D. B. Brewer (North Holland), p174. • B. D. Josephson, Adv. Phys. 14 (1965) 419. • W. E. Lawrence & S. Doniach, “Proc. 12th Int. Nat. Conf. Low Temp. Phys.”, edited by Kanda, p361 (1970). 実験的検証 1. Y. Matsuda, et al., Phys. Rev. Lett. 75 (1995) 4512. 2. K. Kadowaki, et al., Phys. Rev. B56 (1997) 5617. 3. K. Kadowaki, et al., Europhys. Lett. 42 (1998) 203. 4. I. Kakeya, et al., Phys. Rev. B57 (1998) 3108.
Evidence for Josephson Plasma(I) 1. K. Kadowaki, et al., Phys. Rev. B56 (1997) 5617. 2. I. Kakeya, et al., Phys. Rev. B57 (1998) 3108. 3. K. Kadowaki, et al., Europhys. Lett. 42 (1998) 203. longitudinal transverse Sample arrangement inside cavity Instrumental arrangement
Evidence for Josephson Plasma(II) Temperature dependence Size dependnece Resonance field vs. sample size 1. K. Kadowaki, et al., Phys. Rev. B56 (1997) 5617. 2. I. Kakeya, et al., Phys. Rev. B57 (1998) 3108. 3. K. Kadowaki, et al., Europhys. Lett. 42 (1998) 203.
Superconducting Normal Plasma Mode Nambu-Goldstone Mode (Longitudinal Mode) Anderson-Higgs Mechanism c-axis Josephson Plasma Mode Carlson-Goldman Mode Tc 0 Josephson Plasma Mode (III)
Strong, Continuous and Coherent THz Radiation Ozyuzer et al., Science, 318 1291 (2007) Optical image of mesa structure Line width Line width Dn =1 GHz (~0.03 cm-1) Radiation Power, P
Schematic view of the sample Ozyuzer et al., Science, 318 1291 (2007) Mesa Structures (I) 1. Conventional rectangular mesa THz waves THz waves Photo of the sample by SEM 2. Cylindrical mesa 3. Groove type mesa Thickness~1.4 mm 70.1 mm 97.1 mm ~15 mm
FT-IR spectrometer load resistance He flow cryostat Experimental Setup (I) Mesa sample Mesa ab- plane Standard Resistance 10 W c-axis Si Bolometer
Radiation Power P vs. n Coherent Radiation! single layer JJ: Psingle~pW 105-106 times more power! multilayered IJJ: PIJJ ≥ mW - mW Ozyuzer et al., Science, 318 1291 (2007).
Radiation Spectra and Polarization 100~1000times stronger Nearly 100% polarized
Supplemental No. 4 Two Types of Radiation 44Ω<R(Tc) • Reversible(R-type) • Irreversible(IR-type) 56Ω~R(Tc) 140Ω~R(70K) Minami, et al., Physica C (proceedings of M2S) Both can be found in a same mesa In this particular case T< 35K- R-type T>40K- IR-type
Vicinity of Radiation K. Kadowaki, et al., JPSJ Letters 79 (2010) 023703(1-4).
Temperature Dependence • Radiation occurs in a certain range of temperature • The temperature of the mesa is floating up about 10-40 K above the bath temperature. Highly inhomogeneous and Non-equilibrium?? Ozyuzer et al., Science, 318 1291 (2007), Kadowaki, to be published
Geometrical Condition f vs 1/w c0: velocity of light n: refractive index l: wave length of radiation w: narrower width of mesa L w K. Kadowaki, et al., J. Phys. Soc. Jpn. Letters 79 (2010) 023703(1-4).
The Cavity Modes Since w<L, the lowest energy mode would be (01) mode with m=0 and p=1. Experimental result definitely shows that the lowest mode is (10) mode. The reason is not understood yet. M. Tsujimoto, et al., accepted for publication in PRL L w
Patch Antenna Theory Marco Leone, IEEE Trans. Electromag. Compatibility, 45 (2003) 486 y y x x x
Comparison of Experimental Results with Calculations xz-plane xy-plane
Possible excitation modes Klemm and Kadowaki model R. A. Klemm and K. Kadowaki, J. Supercond. Nov. Magn., 23 (2010) 613-616. Symmetric Dipole radiation-like E: linearly polarized IJ Mixed Anti-symmetric Cancelling dipole radiation E: linearly polarized E
Supplemental No. 3-1 Higher Harmonics • Higher harmonics up to 4th order (2.5 THz) • Exponential decay • No sub-harmonics • No harmonics from geometry but from the ac Josephson effect Kadowaki, et al., Physica C 468 (2008) 634-639, Tsujimoto, et al., accepted for Phys. Rev. Lett.
Supplemental No. 3-2 Higher Radiation Modes 90 ° 90 ° Fundamental mode 2nd harmonics
See, M. Tsujimoto, et al., accepted for publication in PRL Formation of the cavity resonance mode D = 2a
Experimental Results of Angular Dependence • At q =0o, P is local minimum. • P has a maximum aroud q = 25o • P0 at q 0o. Cavity resonance mode Uniform mode Model calculations Klemm & Kadowaki, ibid
Supplemental No. 5 Resonant Emission of Two Mesas (Frequency Pulling) n2exp=3.2-3.4 (n2=4) Minami, et al., APL 95 (2009) 232511.
Radiation from Inner-Branches M. Tsujimoto, submitted to PRL
Full Wavelength Resonance Modes See, Poster presentation (P3), by T. Kashiwagi.
Standing Waves Observed? H. B. Wang, et al., Phys. Rev. Lett. 101 (2009) 017006.
Hot Spot and Waves ? H. B. Wang, et al., Phys. Rev. Lett. 101 (2009) 017006.
THz Emission Observed H. B. Wang, et al., arXiv: 1005.0081v1
High Quality Single Crystals High quality single crystal Approx. 5 cm 8 mm Double ellipsoidal mirror infrared furnace Crystal growing equipment
N layers Vdc Giant Josephson junction Emission Mechanism P∝N2 ac-Josephson Effect Multi-stacked Josephson junction Quantum mechanical coherent synchronization Geometrical Resonance Strong, coherent, continuous electromagnetic wave emission LASER
Efficiency of Emission(present status) cf. LASER Diodes: efficiency~70 % For useful applications, a factor of 10-20 should be improved!
THz Sources by Small Scale Solid State Devices THz gap 104 THz gap IMPATT III-V laser 103 Gunn Intrinsic Josephson LASER Optics 102 101 Power (mW) 100 Electronics Quantum cascade laser photomixing Photonics 10-1 10-2 10-3 Microwaves Far infrared light present stage 1 1000 (cm-1) 10 100 10-4 1.0 10 100 0.01 0.1 Frequency (THz) After M. Tonouchi, Nature Photon. 1, 97 (2007).
Comparison of Power Green light: 532 nm Coherent, Continuous, and Compact size (C3 STAR-emitter) LASER pointer (class 2) 1 mW at present x 20 IJJ J-LASER (STAR-emitter) 6 % efficiency 0.3 % only
Applications (Case I) DNA finger print spectrum Guanine (G) Adenine (A) cytosine (C) thymine (T) Medicine, Diagnosis, Drag manufactures, Radiation therapy, Environmental analyses, Variety of imaging, Security, Meta-materials, High-speed communication, Quantum information, Food industries, Fundamental mechanism 0f HTSC, Etc.
Supplemental No. 10-1 Case (II) • imaging After K. Kawase, Optics and Photonics News, Oct. 2004, p.38
Supplemental No. 10-2 Case (III)
Case (IV) Night vision security The infrared camera is available
References 1. Ozyuzer et al., Science, 318 1291 (2007). 2. K. Kadowaki, et al., PhysicaC 468 634-639 (2008). 3. Minami, et al., APL 95 (2009) 232511. 4. J. Leiner, et al., Appl. Phys. Lett. 95 (2009) 252505. 5. C. Kurter, K. E. Gray, J. F. Zasadzinski, L. Ozyuzer, A. Koshelev, Q. Li, T. Yamamoto, K. Kadowaki, W. –K. Kwok, M. Tachikiand U. Welp, IEEE Transactions Appl. Superconductivity 19 (2009) 428-431. 6. K. E. Gray, A. E. Koshelev, C. Kurter, K. Kadowaki, T. Yamamoto, H. Minami, H. Yamaguchi, M. Tachiki, W. –K. Kwok and U. Welp, IEEE Transactions Appl. Superconductivity 19 (2009) 886-889. 7. L. Ozyuzer, et al., Supercond. Sci. Technol. 22 (2009) 114009. 8. R. A. Klemm and K. Kadowaki, J. Supercond. Nov. Magn., 23 (2010) 613-616. 9. K. Kadowaki, et al., J. Phys. Soc. Jpn. Letters 79 (2010) 023703(1-4). 10. Minami, et al., Physica C (proceedings of M2S, available in online) 11. Orita, et al., Physica C (proceedings of M2S, available in online) 12. Tsujimoto, et al., Physica C (proceedings of M2S, available in online) 13. M. Tsujimoto, et al., accepted for publication in PRL. 14. R. Klemm and K. Kadowaki, submitted to Phys. Rev. B, arXiv. Ar0908.4104. 15. R. Klemm et al., submitted to Phys. Rev. B.
C0:velocity of light in vacuum n: refractive index =1/ =4.19 w: width of the sample Resonance mode with Coherent resonant emission occurs when (V) is satisfied. ([d], [w]=[mm]) Summary (I) 1. N intrinsic junctions work together as if they are a big single junction. No su-bharmonics are observed 2. ac Josephson effect is valid (~5 mW) 3. All junctions are coherent! Two mesas synchronize ac Josephson Laser (STAR-emitter)!
Summary (II) 4. Monochromatic spectrum 5. Synchronization Effect of multiple mesas The synchronized resonance between Nn mesas is observed 6. Power: It needs about 20 times more power Pout∼1 mW