Science Fiction Becomes Science Reality:

Towards Cloaking Devices

Meg Noah

7 May 2007

Solid State Physics

“I was perplexed as to what the usefulness of any of the arts might be, with the exception of interior decoration. The most positive notion I could come up with is what I call the canary-in-the-coal-mine theory of the arts. This theory argues that artists are useful to society because they are so sensitive. They are supersensitive. They keel over like canaries in coal mines filled with poison gas, long before more robust types realize that any danger is there.”

--Kurt Vonnegut, Address to the American Physical Society, 1969.

Rhenium diboride resembles both a metal and a crystal in structure. EE "Doc" Smith - 1965 novel Subspace Explorers - describes a super-strong alloy called "leybyrdite", whose key ingredient is rhenium.

In his 1942 story Waldo, Robert Heinlein writes about Waldo F. Jones, who has myasthenia gravis, a muscle disease.

Jules Verne – Nautilus1875

1969 – 2001 Space Odyssey HAL reads lips.

1983 James Bond TV Watch

1867 When he tired of official reports and memoranda and minutes, he would plug his foolscap-sized Newspad into the ship's information circuit and scan the latest reports from Earth. One by one he would conjure up the world's major electronic papers; he knew the codes of the more important ones by heart, and had no need to consult the list on the back of his pad. Switching to the display unit's short-term memory, he would hold the front page while he quickly searched the headlines and noted the items that interested him.

Each had its own two-digit reference; when he punched that, the postage-stamp-sized rectangle would expand until it neatly filled the screen and he could read it with comfort. When he had finished, he would flash back to the complete page and select a new subject for detailed examination.

From 2001: A Space Odyssey , by Arthur C. Clarke. Published by Del Rey in 1968

"Heavier-than-air flying machines are impossible."Lord Kelvin, president, Royal Society, 1895.

Lilienthal's Glider in Flight

"Airplanes are interesting toys but of no military value.“Maréchal Ferdinand Foch, Professor of Strategy, L'École Supérieure de Guerre.

Outline

1. History of negative index of refraction

2. Properties

3. History Channel Movie

4. Experimental Evidence #1 (Microwave)

5. Experimental Evidence #2-3-4 (Visible)

6. Experiment #5 Cloaking (Microwave)

7. Future directions and Summary

And famous last words…

History of Index of Refraction • Ptolemy - angle of refraction was proportional to angle of incidence• 1621 Snell’s Law• 1657 Fermat’s principle of shortest time • 1861 Maxwell’s equations of electrodynamics• 1870 Helmholtz’s reflection/refraction from Maxwell's eq. using BC’s• 1951 Malyuzhinets’ backward media transmission lines

Negative

^

"Airplanes are interesting toys but of no military value.“Maréchal Ferdinand Foch, Professor of Strategy, L'École Supérieure de Guerre.

History of Index of Refraction Negati

ve

^• 1960 Split Ring (μ<0)• 1960 Microwave lens wire grid dielectric (ε<0)

2 2 20 0

21m

CS

LC

2 2

0 2 2 2 21 p p

p j

• 1968 Veselago predicts properties of materials with μ<0 and ε<0 • 1970 beginning with omega shapes and double rings• 2001 Pendry experimental verification of negative index of refraction

"They couldn't hit an elephant at this distance."—Maj. Gen. John Sedgwick, U.S. Army, just before being fatally shot at the Battle of Spotsylvania Court House, May 9, 1864.

Veselago On NIMs

1. Phase Velocity Opposite Group Velocity

2. Reversal of Radiation Pressure

3. Negative Refraction

4. Reversed Doppler Effect

5. Reversed Cerenkov Effect

6. Reversal of Optical Refracting Components

7. Flat Lensing

8. Dispersion Requirement

"Louis Pasteur's theory of germs is ridiculous fiction.“ - Pierre Pachet, Professor of Physiology (Toulouse) 1872

Phase Velocity Reversed

and c ck E H k H E

4cS E H

Left-Handed Right-Handed

"There is no reason anyone would want a computer in their home."--Ken Olson, president, chairman and founder of Digital Equipment Corp., 1977

Group Velocity

"Who the h311 wants to hear actors talk?“ --H.M. Warner, Warner Brothers, 1927.

Reversal of Radiation Pressure

ˆp k x

When photons are absorbed, they impart negative momentum and create radiation tension.

ˆp k x

Left-Handed Right-Handed

When photons are absorbed, they impart negative momentum and create radiation pressure.

"Drill for oil? You mean drill into the ground to try and find oil? You're crazy." --Drillers who Edwin L. Drake tried to enlist to his project to drill for oil in 1859.

Doppler Effect Reversed

k

S

v

detector-source0

group

1v

pu

k

S

v

Rig

ht-H

ande

dLe

ft-H

ande

d

"A guitar’s all right, John, but you’ll never earn your living by it."—John Lennon's Aunt Mimi

Doppler Effect ReversedR

ight

-Han

ded

Left

-Han

ded

"We don't like their sound, and guitar music is on the way out“ -Decca Recording on rejecting the Beatles, 1962.

• Snell’s Law

Veselago’s Negative Index

• Dispersion

• Isotropic Media

22

20il lj ij i jk k k

c

2 22 2 2

2 2 where the index of refraction k n n

c c

incident 2 2 21,2

refracted 1 1 1

sin

sin

pn

p

n

n

"No flying machine will ever fly from New York to Paris."—Orville Wright.

Reversal of Optical Refracting Components

0 50 100 150 200 250-50

-40

-30

-20

-10

0

10

20

30

40

50Positive Index of Refraction - Convex Lens

mm

mm

0 50 100 150 200 250 300-25

-20

-15

-10

-5

0

5

10

15

20

25Negative Index of Refraction - Concave Lens

mm

mm

0 50 100 150 200 250-60

-40

-20

0

20

40

60Positive Index of Refraction - Concave Lens

mm

mm

0 50 100 150 200 250-40

-30

-20

-10

0

10

20

30

40Negative Index of Refraction - Convex Lens

mm

mm

"I think there is a world market for maybe five computers."--Thomas Watson, chairman of IBM, 1943.

0 50 100 150 200 250 300 350 400-6

-4

-2

0

2

4

6Negative Index of Refraction - Thin Plate

mm

mm

Flat Lensing

0 50 100 150 200 250 300 350 400-10

-8

-6

-4

-2

0

2

4

6

8

10Positive Index of Refraction - Thin Plate

mm

mm

0 200 400 600 800 1000 1200 1400 1600-15

-10

-5

0

5

10

15Negative Index of Refraction - Plate

mm

mm

0 200 400 600 800 1000 1200 1400 1600-10

-8

-6

-4

-2

0

2

4

6

8

10Positive Index of Refraction - Plate

mm

mm

“This ‘telephone’ has too many shortcomings to be seriously considered as a means of communication. The device is inherently of no value to us.” - Western Union internal memo, 1876

Dispersion Requirement

"Stocks have reached what looks like a permanently high plateau."—Irving Fisher, Professor of Economics, Yale University, 1929.

• ε and μ cannot both be negative at all frequencies because it would lead to a negative total energy W.

2 2

2 2

in absence of dispersionW E H

W E H

Veselago Summary

"The wireless music box has no imaginable commercial value. Who would pay for a message sent to nobody in particular?“ --David Sarnoff’ s associates in response to his urgings for investment in the radio in the 1920’s.

Physics Nonmagnetic Approximation

Exact Formula

Snell’s Law, Doppler, Cherenkov

Fresnel Formulas

Reflection Coefficient (normal incidence)

No-reflection condition

Brewster Law

n n incident 2 2 2

1,2refracted 1 1 1

sin

sin

pn

p

incident 21,2

refracted 1

sin

sinn

n z 1 i 2 r

1 i 2 r

cos cos

cos cos

n nr

n n

2 i 1 r

2 i 1 r

cos cos

cos cos

Z Zr

Z Z

1 2

1 2

n nr

n n

2 1

2 1

Z Zr

Z Z

1 2n n 2 1Z Z

2 2 1 1 2

1 2 2 1 1

tan

tan n

Permittivity

ε ≥ 0ε < 0μ ≥ 0

μ < 0

Per

mea

bili

ty

ε < 0μ < 0ε ≥ 0

μ ≥ 0

Metals like gold

Semiconductors

Opaque

Opaque

Plasmas

Fine wire structuresConventional materials

Microstructured magnets

Split ringsMetamaterials

"But what ... is it good for?" --Engineer at the Advanced Computing Systems Division of IBM, 1968, commenting on the microchip.

Material Taxonomy of εμ

n

n

"Forget it, Louis; no Civil War picture ever made a nickel." — Irving Thalberg's advice to Louis B. Mayer regarding Gone With the Wind

Central Question

• How can we create materials with controllable the permittivity and permeability?

Approaches To MaterialsMetamaterials Photonic Crystal Nanoscaled

Create ‘effective’ mediumWhere structural propertiesDominate and yield μeff and εeff

Use constructive and destructiveinterference to engineer propertiesof light ω(k) (changing neff and meff)band structureband gapsdefect states

Permittivity• Permittivity is a physical quantity that describes how an electric field

affects and is affected by a dielectric medium, and is determined by the ability of a material to polarize in response to the field, and thereby reduce the field inside the material. Thus, permittivity relates to a material's ability to transmit (or "permit") an electric field. (Wiki)

Manipulating Permittivity

2

0

2

2

1

1

p

p

Aig

2

eff eff

4

properties manipulated by ,

p

ne

mn m

2 2

2,

81 cv

c v

eW E E E dx

m

Crystal – optical band structure

Wcv is the product of the Brillouin-zone-average transition probability at the energy E and the joint density of states probability, Jcv(E), and is a broadening function due to scattering.

Metal

2 4 6 8 10

x 1016

-4

-3

-2

-1

0

1

[Hz]

Permittivity of Gold (Drude) ωp=1.37e16 Hzg0=4.08e13 Hz

For most metalsωp in optical/UV

Manipulating Permittivity

Permeability

• Permeability is the degree of magnetization of a material that responds linearly to an applied magnetic field. (Wiki)

10 211

715 120

2 2 22

ˆ =paramagnetic termˆ ˆ=bound particle =diamagnetic term10 Hz 10 Hz10 Hz

ˆˆ ˆ ˆ ˆ2 8

B

e e

HH HE h E hE h

p q BH V L B R

m m

, n B n BE k T E k Tn

n n

M H T M e e

where

1 n

n

E HM H

V H

20

2

0 diamagnetic1

0 paramagnetic

MF

V H H

01

Manufacturing Permeability

Manufacturing Permeability

Manufacturing Permeability

Experimental Evidence #1

(a) and (b) are from: R. A. Shelby, D. R. Smith, S. Schultz, Appl. Phys. Lett. 78, 489 (2001).Copyright (2001) American Institute of Physics. Photo ( c) from December 2003 Physics Today is metamaterial used for microwave experiments.

c

Negative Index of Refraction at Microwave Wavelengths

Experimental Evidence #1

Experimental Evidence #1

Experimental Evidence #1

December 2003 Physics Today.

Experimental Evidence #2

Negative Index of Refraction at Visible Wavelengths

Zhang, Shuang, Wenjun Fan, Kevin J. Malloy, Steven R. J. Brueck, Nicolae C. Panoiu and Richard M. Osgood, "Demonstration of metal–dielectric negative-index metamaterials with improved performance at optical frequencies," J. Opt. Soc. Am. B, Vol. 23, No. 3 (2006) 434-438

Experimental Evidence #2

Zhang, Shuang, Wenjun Fan, Kevin J. Malloy, Steven R. J. Brueck, Nicolae C. Panoiu and Richard M. Osgood, "Demonstration of metal–dielectric negative-index metamaterials with improved performance at optical frequencies," J. Opt. Soc. Am. B, Vol. 23, No. 3 (2006) 434-438

Experimental Evidence #3

Experiment #4 - Superlensing

Experimental Evidence #5

Cloaking with Microwaves

February 2007 Physics Today.

Experimental Evidence #5

February 2007 Physics Today.

Summary/Future Directions

• Summary– Negative Index of Refraction Confirmed– Lots of Applications

• Antennas, Communications, Cloaking• Superlenses, Filters, Superconductors

• Challenges– Losses– Scaling for IR/Vis/UV

            A Route to Transparency: A "cloak" invented by Susumi Tachi suggests a path to invisibility, or at least an interesting form of camouflagehttp://www.ee.duke.edu/~drsmith/cloaking.html