Coherent THz Radiation from Intrinsic Josephson Junctions

University of University of TsukubaTsukuba

Photonics and Quantum Optics for the Creation of New Functions“Emission of Continuous THz Waves by Layered Superconductors and Its Applications”

Coherent THz Radiation from Coherent THz Radiation from Intrinsic Josephson JunctionsIntrinsic Josephson Junctions

http://kadowaki.ims.tsukuba.ac.jp/, http://www.tsukuba.ac.jp

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

Lecture given at the Institute of Radio-Engineering and Electronics, Russian Academy of Sciences, Moscow, Russia, July 19th, 2010.



Outline of TalkOutline of TalkIssues 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



100 103 106 109 1012 1015 1018 1021 1024

kiro mega giga tera peta exa zetta yotta

THTHzz

1010 1011 1012 1013 1014

FIR MIR NIR visible

frequency 10[GHz] 100[GHz] 1 [THz] 10[THz] 100 [THz] wave length 3[cm] 3[mm] 300[m] 30[m] 3[m] wave number 0.33[cm-1] 3.3[cm-1] 33[cm-1] 330[cm-1] 3300[cm-1]

Molecular SpectroscopyAtomic spectroscopy

Macromolecule fundamental mode electronic transition rotational mode higher harmonics

MF VHF SHF HF UHF EHF

microwaveElectronicsElectronics PhotonicsPhotonics

x-ray -ray

FREQUENCY (Hz)FREQUENCY (Hz)



Characteristics of THz from Characteristics of THz from IJJ’sIJJ’s

Advantages1. New generation mechanism: using collective modes in

superconductors (Josephson plasma modes, not quantized energy levels)

2. Vibrational and 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 K5. Nondestructive and noninvasive: non-ionizing, but thermal

effects6. Compact and all solid state devices: small, light, high power

efficiency7. Imaging purposes: medical use, security issues, defense, food

industries, quality control, etc.8. Communication: high speed communications at near distances

Disadvantages1. Necessary to cool below Tc=80 K



BiBi22SrSr22CaCuCaCu22OO8+8+

Intrinsic Josephson JunctionsIntrinsic Josephson Junctions

1.53 nm

Bi-2212 order parameter

Bi2O2

Bi2O2

CuO2

CuO2

CuO2

CuO2

CuO2

CuO2

SrO

SrO

SrO

SrO

Intrinsic inhomogeneity

multilayer effects

1 m=760 layers

unit cell of Bi2212

Schematic view of rectangular mesa

Ozyuzer et al., Science, 318 1291 (2007)

1. R. Kleiner et al., Phys. Rev. Lett. B49 (1992) 23940

2. G. Oya, et al., Jpn. J. Appl. Phys. 31 (1992) L829..

3. K. Kadowaki & T. Mochiku, Physica B195-196 (1994) 2239.



Josephson plasmaJosephson plasmajA

1. P. W. Anderson, “Lectures on The Many-Body Problem” (vol. II), edited by E. R. Caianiello, Academic press, 1964, p113.

2. B. D. Josephson, “Quantum Fluids, Proc. Susex Univ. Symp.”, 16-20, 1965, ed by D. B. Brewer (North Holland), p174.

3. B. D. Josephson, Adv. Phys. 14 (1965) 419.4. W. E. Lawrence & S. Doniach, “Proc. 12th Int.

Nat. Conf. Low Temp. Phys.”, edited by Kanda, p361 (1970).

meV

jed cp

602

/8

1002/ ppf Gc/s

Single junction Multi-junctions

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.

microw

ave



Evidence for Evidence for Josephson PlasmaJosephson Plasma (I)(I)

Instrumental arrangementSample arrangement inside cavity

longitudinal

transverse

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.



Evidence for Evidence for Josephson PlasmaJosephson Plasma (II)(II)

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.

Temperature dependence Size dependnece Resonance field vs. sample size



Josephson Plasma Mode (II)Josephson Plasma Mode (II)



Josephson Plasma Mode (III)Josephson Plasma Mode (III)

NormalSuperconducting

Plasma Mode

Tc

c-axis Josephson Plasma Mode

0

An

de

rso

n-H

igg

s M

ech

anis

mm

nep

22 4

Jps

c

n e

m

c

22

2

2

4

Carlson-Goldman Mode

Nambu-Goldstone Mode

(Longitudinal Mode)



Strong, Continuous and Strong, Continuous and Coherent THz RadiationCoherent THz Radiation

9 10 11 12 13 14 150

50

100

150

200

Inte

nsi

ty (

a.u.)

wavenumber k (cm- 1)

V=0.826 Vk=0.374 cm-1

k/k=0.0316 resolution limit

2nP rad

Line width

=1 GHz ( ～ 0.03 cm-1) Radiation Power, P

Line width

Optical image of mesa structure

Ozyuzer et al., Science,

318 1291 (2007)



Photo of the sample by SEM

Mesa Structures (I)Mesa Structures (I)

1. Conventional rectangular mesa

2. Cylindrical mesa 3. Groove type mesa

Schematic view of the sampleOzyuzer et al., Science, 318 1291 (2007)

70.1 m97.1 m

～ 15 m

Thickness ～ 1.4 m

THz waves

THz waves



Experimental Setup (I)Experimental Setup (I)

He flow cryostat

Mesa

FT-IR spectrometer

Si Bolometer

c-axis

ab-plan

e

load resistance

Mesa sample

Standard Resistance

10



Radiation Radiation Power Power PP vs. vs.

nn2nP rad

Coherent Radiation!single layer JJ ： Psingle ~ pW

multilayered IJJ ：PIJJ ≥ W - mW

１０ 5-106 times more power!

Ozyuzer et al., Science, 318 1291 (2007).



Radiation Spectra and Radiation Spectra and PolarizationPolarization

100 ～ 1000 times stronger Nearly 100% polarized



Two Types of RadiationTwo Types of Radiation• Reversible(R-type)• Irreversible(IR-type)

44Ω<R(Tc)

140Ω ～ R(70K)

56Ω ～ R(Tc)

Both can be found in a same mesa

T< 35K - R-typeT>40K - IR-type

In this particular case

Minami, et al., Physica C (proceedings of M2S)

Supplemental No. 4



Vicinity of RadiationVicinity of Radiation

K. Kadowaki, et al., JPSJ Letters 79 (2010) 023703(1-4).



Temperature Temperature DependenceDependence

• Radiation occurs in a certain range of temperature

• The temperature of the mesa is floating up about 10-40 K above the bath temperature.

0 10 20 30 40 50 600.0

0.5

1.0

Norm

aliz

ed In

tensi

ty (

arb

.)

T (K)

Highly inhomogeneous and

Non-equilibrium??Ozyuzer et al., Science, 318 1291 (2007), Kadowaki, to be published



Geometrical ConditionGeometrical Condition

f vs 1/w

c0: velocity of light

n: refractive index : wave length of radiation

w: narrower width of mesa

nw

c

n

cf

200

w

L

K. Kadowaki, et al., J. Phys. Soc. Jpn. Letters 79 (2010) 023703(1-4).



The Cavity ModesThe Cavity Modes

Since w<L, the lowest energy mode would be (01) mode with m=0 and p=1.

21

22

0

J

22

L

p

w

mk

ckkn

c

hN

eV

N

eV

mp

mpmpmp

L

w

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



Patch Antenna TheoryPatch Antenna Theory

Marco Leone, IEEE Trans. Electromag. Compatibility, 45 (2003) 486

x

yy

xx



Comparison of Experimental Comparison of Experimental Results with CalculationsResults with Calculations

xz-plane

xy-plane



Possible excitation Possible excitation modesmodes

Symmetric

Dipole radiation-likeE: linearly polarized

Klemm and Kadowaki model

IJ

Cancelling dipole radiationE: linearly polarized

Anti-symmetric

E

MixedMixed

R. A. Klemm and K. Kadowaki, J. Supercond. Nov. Magn., 23 (2010) 613-616.



Higher HarmonicsHigher 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. 3-1



Higher Radiation ModesHigher Radiation Modes

Fundamental mode 2nd harmonics

90 ° 90 °




an

c mpmp

20

0

ar

z

r

E

D = 2a

a4

Formation of the cavity resonance mode

See, M. Tsujimoto, et al., accepted for publication in PRL



1. At =0o, P is local minimum.2. P has a maximum aroud =

25o

3. P0 at 0o.

Cavity Cavity resonance moderesonance mode Uniform modeUniform mode Model calculationsModel calculations

Experimental Results ofExperimental Results ofAngular Dependence Angular Dependence

Klemm & Kadowaki, ibid



Resonant Emission of Resonant Emission of Two Mesas (Frequency Two Mesas (Frequency

Pulling)Pulling)(n2=4)n2

exp=3.2-3.4

Supplemental No. 5

Minami, et al., APL 95 (2009) 232511.



Radiation Radiation from Inner-Branchesfrom Inner-Branches

M. Tsujimoto, submitted to PRL



Full Wavelength Full Wavelength Resonance ModesResonance Modes

See, Poster presentation(P3), by T. Kashiwagi.



Standing Waves Standing Waves Observed?Observed?

H. B. Wang, et al., Phys. Rev. Lett. 101 (2009) 017006.



Hot Spot and Waves ?Hot Spot and Waves ?

H. B. Wang, et al., Phys. Rev. Lett. 101 (2009) 017006.



THz Emission ObservedTHz Emission Observed

H. B. Wang, et al., arXiv: 1005.0081v1



High Quality Single CrystalsHigh Quality Single Crystals

Crystal growing equipment

Double ellipsoidal mirror infrared furnace

High quality single crystal

Approx. 5 cm

8 mm



AB

0

2

t

Ve

dt

d

J

dc

0

2

dcdc V

h

eVf

eV

J

2

Multi-stacked Josephson junction

Giant Josephson junction

1

2

21

Vdc

P∝N2 ac-Josephson Effect

N layers

Emission Emission MechanismMechanism

Geometrical ResonanceGeometrical ResonanceQuantum mechanical Quantum mechanical coherent synchronizationcoherent synchronization

Strong, coherent, continuous electromagnetic wave emissionStrong, coherent, continuous electromagnetic wave emission

LASERLASER



Efficiency of EmissionEfficiency of Emission（（ present statuspresent status ））

at present desired in future

input power 17 ～ 20 mW 10-20 mW

output power (at detector) ～ 50 W (360 nW ) 1 mW

area energy density ～ 10 W/cm2 ～ 100 W/cm2

volume energy density ～ 3000 W/cm3 ～ 5x104 W/cm3

efficiency ～ 0.3% ～ 5-10%

For useful applications,For useful applications,a factor of 10-20 should be improved!a factor of 10-20 should be improved!

cf. LASER Diodes: efficiency ～ 70 %



THz gap

0.01 0.1 1.0 10 100

10-3

100

10-1

10-2

10-4

101

102

103

104

Pow

er (

mW

)

Frequency (THz)

THz THz gapgap

Opt

ics

Pho

toni

cs

Electronics

photomixing

Qu

antu

m c

asca

de

lase

r

III-V

lase

r

Gunn

IMPATT

Intrinsic Josephson

LASER

10 1001 1000 (cm-1)

Microwaves Far infrared lightpresent stage

After M. Tonouchi, Nature Photon. 1, 97 (2007).

THz Sources by Small Scale Solid State Devices



Comparison of PowerComparison of Power

WP 5030

LASER pointer(class 2)

Green light: 532 nm

IJJ J-LASER(STAR-emitter)

at present x 20

1 mW

efficiency0.3 % only 6 %

Coherent, Continuous,and Compact size(C3 STAR-emitter)



Applications (Case I)Applications (Case I)DNA DNA

finger print finger print spectrumspectrum

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.



Case (II)Case (II)

• imaging

After K. Kawase, Optics and Photonics News, Oct. 2004, p.38




Case (III)Case (III)Supplemental

No. 10-2



Case (IV)Case (IV)

Night vision

securityThe infrared camera is available



ReferencesReferences1. 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.



Summary (I)Summary (I)

N

V

h

e obsobs

2

)029.1(6731617.568

791523.0

001.0

5940.483

2m

f

V

e

hN

obs

obs

1.

2.

ac Josephson effect is valid

3.2NPobs

All junctions are coherent!Two mesas synchronize

N intrinsic junctions work together as if they are a big single junction.

(V)

Coherent resonant emission occurs when

w

thicknessdVobs

)(2.48

is satisfied. ([d], [w]=[m])

nw

cobs 2

0 C0: velocity of light in vacuumn: refractive index =1/ =4.19w: width of the sample

( ～ 5 W)

ac Josephson Laser (STAR-emitter)!

Resonance mode with ,...2/,,2 wwwNo su-bharmonics are observed



Summary (II)Summary (II)4. Monochromatic spectrum GHzf 0.1

5. Synchronization Effect of multiple mesas5. Synchronization Effect of multiple mesas

The synchronized resonance between Nn mesas is observed

2nNP

6. Power: It needs about 20 times more power6. Power: It needs about 20 times more power

PPoutout ∼∼1 mW1 mW



Thank you for your attention

Documents

Coherent THz Radiation from Intrinsic Josephson Junctions