Optical device

A structure exhibiting a photonic band gap, said structure comprising a material, extending in two dimensions, said material comprising first and second regions, said first regions having a first refractive index spaced from one another by a second region or regions, said second regions having a second refractive index, said first and second regions defining a quasicrystal, said quasicrystal exhibiting long range order but short term disorder, and exhibiting n-fold symmetry, wherein n is greater than or equal to two, said quasicrystal creating a photonic band gap extending in at least said two dimensions.

A method of forming a structure exhibiting a photonic band gap, the method comprising the steps of:

• providing a material, extending in two dimensions, said material having a relatively low index of refraction, less than or equal to three, and
• forming in said material first and second regions, said first regions having a first refractive index, the first regions being spaced apart by a second region or regions, said second regions having a second refractive index, the first and second regions defining a quasicrystal, said quasicrystal exhibiting long range order but short term disorder and exhibiting an n-fold symmetry where n is greater than or equal to two, whereby said quasicrystal provides a photonic band gap extending in at least said two dimensions.

A method of forming a structure exhibiting a photonic band gap, the method comprising:

• providing a material extending in two dimensions and forming in said material first regions, having a first refractive index, the first regions being spaced apart by a second region or regions of a second refractive index, the regions defining a quasicrystal exhibiting long range order but short term disorder and exhibiting n-fold symmetry, wherein n≧12, whereby to create a photonic band gap extending in at least said two dimensions.

A method of forming a structure exhibiting a photonic band gap, the method comprising:

• providing a material, extending in two dimensions, and etching the material to remove material in predetermined areas, the etching extending in a direction perpendicular to said two dimensions, whereby to define first regions having a first refractive index spaced by a second region or regions having a second refractive index, whereby to define a quasicrystal exhibiting long range order but short term disorder and exhibiting n-fold symmetry wherein n is greater than or equal to two, whereby to create a photonic band gap extending in at least said two dimensions, and
• wherein the ratio of the area of the first regions to the area of the second regions is relatively low, being less than 35%.

A structure exhibiting a photonic band gap,

• wherein the structure includes a material comprising first and second regions, said first regions having a first refractive index and spaced from one another by at least a second region, said second region having a second refractive index, said first and second regions providing a quasicrystal exhibiting a photonic band gap, such as to modify the properties of the material to induce a significant non-linear effect wherein the refractive index of the structure is dependent upon the power of light incident on the structure.

An optical device comprising a body having at least one path there through for the transmission of optical radiation wherein the transmission characteristics of said radiation when traversing said path are constrained by a first and second regions disposed within said body, said first and second regions comprised of at least one material exhibiting a photonic band gap wherein said first and second regions are positioned relative to one another so that an evanescent field associated with the photonic band gap of said first region interacts with an evanescent field associated with the photonic band gap of said second region to cause said transmission characteristic to be essentially non-linear, asymmetric or controllable.

An optical device having an optical transmission path through first and second adjacent areas, each area comprised of first and second regions, said first region comprising a plurality of first regions, each of said first region having a first refractive index, said first regions spaced apart by at least one second region, said second region having a second refractive index, said first and second regions defining a quasicrystal structure having a photonic band gap, and each such quasicrystal structures having defects therein to create photonic states within the band gap and associated evanescent fields, the evanescent fields of the first and second areas being coupled so as to permit transmission within the photonic band gap, the transmission characteristic being non-linear or asymmetric.

An optical device having an optical transmission path through first and second adjacent areas, each area being formed from a layer of material comprising first and second regions, said first regions having a first refractive index and being spaced apart by at least one second region, having a second refractive index, the first and second regions defining a quasicrystal structure having a photonic band gap, the photonic band gaps in the two areas having different values, whereby light incident on the one area adjusts the band gap value relative to the band gap of the other area.