Left-Handed Materials

Presented by

Lukasz Blaszczyk

Left-Handed Materials (LHM)

In 1968 a Russian physicist Victor Veselago published a theoretical paper examining properties of materials with a negative refractive index.

Predicted light would be refracted in the opposite direction to normal materials.

Thought a perfect lens could be created.

Light in Matter

Light interacts with surrounding material depending on the material's properties.

Dependant on the Permeability and Permittivity of the material.

Light incident from one medium into a second medium will either reflect or refract.

Refraction

The bending of light at the interface of two materials is called refraction.

Described by Snell's Law.

Depends on Angle of incidence.

Depends on index of refraction of materials.

In LHM light refracts in opposite direction.

Perfect Lenses

There are no ideal lenses.

Even the most precise lenses exhibit aberrations.

Diffraction at the endges of lenses distorts images.

In LHM with negative index of refraction this diffraction limit may be countered.

Criticism of LHM

Physicists from Madrid argued light would have to have infinite energy in a LHM to create a perfect lens.

Others at University of Texas at Austin claimed while 'phase front' traveled in a negative direction the 'group front' traveled in the positive. Leading to an infinite speed of light.

John Pendry of Imperial College in London however showed both teams have errors in their calculations.

Composite LHM

In April 2003 a team from MIT and Harvard observed Snell's Law in a composite LHM.

The material acted as theory for a negative index of refraction.

Worked only in the microwave spectrum.

New Materials

First example of amphoteric material created at National Renewable Energy Lab in Colorado in October 2003.

Amphoteric material can refract light in a negative or positive way depending on the angle of incidence.

Operates in the visible spectrum (442nm and 532 nm shown below.

Can refract a ballistic beam of electrons.

Inhibits reflection at the media interface.

References

Left-Handed Materials Debate Heats Up, http://focus.aps.org/story/v9/st23

Left Handed Materials, http://www.aip.org/enews/physnews/2003/split/628-1.html

Doubt cast on 'left-handed' materials, http://physicsweb.org/article/news/6/5/4/1

A New Type of Medium Interface Features Negative Refraction,http://www.aip.org/enews/physnews/2003/split/657-3.html

Is There a Perfect Lens?, http://www.photonics.com/spectra/tech/XQ/ASP/techid.1398/QX/read.htm

Left Handed Media (LHM) Righted, http://www.utexas.edu/research/cemd/nim/

Left-Handed Metamaterials, http://physics.ucsd.edu/~drs/left_home.htm

Experimental Verification of a Negative Index of Refraction, Science, 292, 77 (2001). http://www.sciencemag.org/cgi/reprint/292/5514/77.pdf

Lukasz Blaszczyk

2003-09-08T21:15:43