We have experimentally realized an ultrashort focal length planoconcave microlens in an InP/InGaAsP semiconductor two-dimensional photonic crystal with negative index of refraction n = -0.7. At wavelength 1.5 microns, the lens exhibits ultrashort focal lengths of 12 microns (~ 8x wanelength) and numerical aperture close to unity.

We show that a binary-staircase optical element can be engineered to exhibit an effective negative index of refraction, thereby expanding the range of optical properties theoretically available for future optoelectronic devices. The mechanism for achieving a negative-index lens is based on exploiting the periodicity of the surface corrugation.

Exact solutions are obtained for all the modes of wave propagation along an anisotropic cylindrical waveguide. Closed-form expressions for the energy flow on the waveguide are also derived. For extremely anisotropic waveguide where the transverse permittivity is negative while the longitudinal permittivity is positive, only transverse magnetic (TM) and hybrid modes will propagate on the waveguide.

We show that a metamaterial consisting of aligned metallic nanowires in a dielectric matrix has strongly anisotropic optical properties. For long wavelngths, the longitudinal SPR, the material exhibits positive transverse permittivity and negative longitudinal permittivity, relative to the nanowires axis, enabling the achievement of broadband all-angle negative refraction and superlens imaging.

Refraction at a smooth interface is accompanied by momentum transfer normal to the interface. We show that corrugating an initially smooth, totally reflecting, non-metallic interface provides a momentum kick parallel to the surface, which can be used to refract light negatively or positively.

We show that with an appropriate surface modification, a slab of photonic crystal can be made to allow wave transmission within the photonic band gap. Furthermore, negative refraction and all-angle negative refraction _AANR_ can be achieved by this surface modification in frequency windows that were not realized before in two-dimensional photonic crystals _C.

Negative refraction is demonstrated in one-dimensional _1D_ dielectric photonic crystals _PCs_ at microwave frequencies. Focusing by plano-concave lens made of 1D PCs due to negative refraction is also demonstrated.

Remarkably slow propagation of microwaves in two different classes of left-handed materials LHM's is reported from microwave-pulse and continuous-wave transmission measurements.

We derive a general theory for imaging by a flat lens without optical axis. We show that the condition for imaging requires a material having elliptic dispersion relations with negative group refraction.

We demonstrate focusing of a plane microwave by a planoconcave lens fabricated from a photonic crystal having a negative refractive index and left-handed electromagnetic properties.

Artificial materials with negative refractive index are called left handed materials becaue of the unusual electromagnetic wave propagation in them. In these material the wave travel backwards while the energy propagates along the incident direction, contrary to the naturally available materials.

An intriguing property of the left-handed material is negative refraction. The optical properties of materials that are transparent to electromagnetic (EM) waves can be characterized by an index of refraction. Given the direction of the incident beam at the interface of vacuum and the material, the direction of the outgoing beam can be determined using Snell's formula.

Negative refarcation can be exploted to make novel lenses having flat surfaces. All conventional lenses have curved surfaces due to positive index of refraction. However, negative index of refraction allows a flat slab of a material to behave as a lens and focus electromagnetic waves as well as produce a real 3-D image. We have demonstrated this unique feature of imaging by a flat lens, using the phenomenon of all-angle negative refraction in a photonic crystalline material.

We explore design and fabrication techniques that allow photonic cristals and metamaterials to possess left handed behavior.