Method for guiding an electromagnetic radiation, in particular in an integrated optical device
First Claim
1. A method for guiding electromagnetic radiation, comprising:
- providing a photonic crystal made of a bulk material having a first refractive index, said photonic crystal having, at least in a portion thereof, a periodic array of regions with a second refractive index different from the first refractive index, said regions having predetermined dimensions and said array having a predetermined period; and
feeding to said region of said photonic crystal an electromagnetic radiation having a wavelength in the fundamental photonic band of said photonic crystal, wherein said wavelength, the difference between said first and second refractive indices, the dimensions of said regions and the period of said array are so related that, starting from an isotropic distribution of wave vectors, having group velocity vectors which correspond to said wave vectors, of said electromagnetic radiation within a first angular range that is twice the angular extension of a first irreducible Brillouin zone of said photonic crystal, the group velocity vectors corresponding to said wave vectors being rearranged as concerns direction and module so that at least 50% of said group velocity vectors are directed within a second angular range that is about one-third of said first angular range and a width at half-maximum of the distribution of the modules of said group velocity vectors is lower than about two-thirds of said second angular range.
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Abstract
A method for guiding electromagnetic radiation by providing a photonic crystal made of a bulk material with a predetermined refractive index and having a periodic array of holes with predetermined radius, and feeding to that region an electromagnetic radiation having a wavelength in the fundamental photonic band and so related to the refractive index of the bulk material, to the radius of the holes and to the period of the array that, starting from an isotropic distribution of the wave vectors within a first angular range that is twice the angular extension of the first irreducible Brillouin zone of the photonic crystal, the corresponding group velocity vectors are rearranged as concerns direction and module so that at least 50% of them become directed within a second angular range that is about one-third of the first angular range and the width at half-maximum of the distribution of the modules of the vectors is lower than about two-thirds of the second angular range.
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Citations
19 Claims
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1. A method for guiding electromagnetic radiation, comprising:
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providing a photonic crystal made of a bulk material having a first refractive index, said photonic crystal having, at least in a portion thereof, a periodic array of regions with a second refractive index different from the first refractive index, said regions having predetermined dimensions and said array having a predetermined period; and feeding to said region of said photonic crystal an electromagnetic radiation having a wavelength in the fundamental photonic band of said photonic crystal, wherein said wavelength, the difference between said first and second refractive indices, the dimensions of said regions and the period of said array are so related that, starting from an isotropic distribution of wave vectors, having group velocity vectors which correspond to said wave vectors, of said electromagnetic radiation within a first angular range that is twice the angular extension of a first irreducible Brillouin zone of said photonic crystal, the group velocity vectors corresponding to said wave vectors being rearranged as concerns direction and module so that at least 50% of said group velocity vectors are directed within a second angular range that is about one-third of said first angular range and a width at half-maximum of the distribution of the modules of said group velocity vectors is lower than about two-thirds of said second angular range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A device for guiding electromagnetic radiation, comprising:
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a photonic crystal made of a bulk material having a first refractive index, said photonic crystal having, at least in a portion thereof, a periodic array of regions with a second refractive index different from the first, said regions having predetermined dimensions and said array having a predetermined period; an optical source optically linked to said region of said photonic crystal and suitable to generate an electromagnetic radiation having a wavelength in the fundamental photonic band of said photonic crystal, said wavelength being so related to a difference between said first and second refractive indices, to dimensions of said regions and to a period of said array that, starting from an isotropic distribution of wave vectors, having group velocity vectors which correspond to said vectors, of said electromagnetic radiation within a first angular range that is twice an angular extension of a first irreducible Brillouin zone of said photonic crystal, the group velocity vectors corresponding to said wave vectors being rearranged as concerns direction and module so that at least 50% of said vectors are directed within a second angular range that is about one-third of said angular range and a width at half-maximum of the distribution of the modules of said vectors is lower than about two-thirds of said second angular range. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification