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Negative refraction in photonic crystals Mike Kaliteevski Durham University
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Outine Photonic Crystals: Introduction Negative refraction in left-handed material Non-diffracting beams Electromagnetic wiggler
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Bragg reflector r n1n1 n2n2 t
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n1n1 r n1n1 d2d2 n2n2
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r n1n1 n2n2 n1n1 n2n2 d2d2 d2d2 Periodic sequence of the pairs of quarterwave layers is the Bragg reflector. The waves, reflected from different boundaries experience positive interference (enforce each other).
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Bragg reflector
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Bloch theorem. Dispersion relations
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BR = c/(n 1 d 1 +n 2 d 2 ) BR Formation of the photonic band gap in periodic structures
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Probability of spontaneous emission
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L
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Microcavity
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Electric field Magnetic field
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Probability of spontaneous emission L L
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2D Photonic crystal
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1D photonic crystal
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2D photonic crystal
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Dispersion relations in 2D photonic crystal
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Plane waves method Bloch theorem Wave equation Lattice vector Reciprocal lattice vector
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Plane waves method Wave equation Reciprocal lattice vector
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2D photonic crystals HE
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Disperison relations H E
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Complete PBG
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Transmissiom of light Experiment Modelling
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PC spectral filter
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Defects in photonic crystals m = 1 m = 2 m = 0m = 3
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Photonic crystal waveguide
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PC Waveguide
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OE_15_12982 3D Photonic crystals
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Transmission of light and bandstructure in opals and inverse opals.
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Photonic microstructures in nature
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Negative refraction in left-handed material
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Right - hand materials Usual electromagnetic word
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Left - hand materials V.G.Veselago, Electrodinamics of the materials with negative dielectric and magnetic constant (1967) Inversed Doppler effect Inversed Vavilov – Cherenkov effect Negative refraction
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Refraction KτKτ KτKτ
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KτKτ KτKτ Positive refraction
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KτKτ KτKτ Negative refraction
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Left - hand materials Negative refraction Flat Lense
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L n1n1 n2n2 A D Flat lence n1n1 n 2 =-n 1
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Superlence ??? Comment: John Michael Williams, Some Problems with Negative Refraction, Phys. Rev. Lett. 87, 249703 (2001)Phys. Rev. Lett. 87, 249703 (2001) Comment: G. W. 't Hooft, Comment on “Negative Refraction Makes a Perfect Lens”, Phys. Rev. Lett. 87, 249701 (2001)Phys. Rev. Lett. 87, 249701 (2001) Reply: M. Nieto-Vesperinas and N. Garcia, Nieto- Vesperinas and Garcia Reply:, Phys. Rev. Lett. 91, 099702 (2003)Phys. Rev. Lett. 91, 099702 (2003) J. B. PendryJ. B. Pendry, Negative Refraction Makes a Perfect Lens, Phys. Rev. Lett. 85, 3966 - 3969 (2000) Автор ввел понятие "суперлинза",...утверждая, что для этого устройства отсутсвует дифракционный предел. Наверное, наиболее убедительное доказательство ошибочности подобного рода утверждений можно найти в... [ В.Г.Веселаго, УФН, 173 (7) 790 (2003) ] With a conventional lens sharpness of the image is always limited by the wavelength of light. An unconventional alternative to a lens, a slab of negative refractive index material, has the power to focus all Fourier components of a 2D image, even those that do not propagate in a radiative manner. Such “superlenses”.....
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Realization of left-hand materials Metamaterials Photonic crystals
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Negative refraction in photonic crystals v gr <0 v gr >0 2D hexagonal metallic PC, D =200 microns, d = 60 microns
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Negative refraction in 2D hexagonal photonic crystals
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Refraction of wave in photonic crystal prism v gr <0 v gr >0
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Refraction of wave in photonic crystal prism
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Experimental study of negative refraction
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Experimental study of negative refraction of THz using QCL
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SIGNAL WITHOUT SAMPLE Negatively refracted beam
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Non-diffracting beams W
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L l1l1 l2l2 A D n1n1 n2n2 n1n1
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Negative refraction in 1D photonic crystals n1 n2 d 1 d 2
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Problem: Veselago lens based on 1D PC Bragg reflector does not work. Because system is anisotropic: negative effective mass is required for negative refraction, and for 2 nd, 4 th, etc bands m z 0
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n1n2 d 1 d 2 x z K 0 Field of the wave in the structure
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Modes in Bragg reflector
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Amplitude of waves
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High contrast: n 1 =3.7 n 2 =1 Low contrast: n 1 =1.4 n 2 =1.8
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Negative refraction
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Normal channelling
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Low contrast: n 1 =1.4 n 2 =1.8 Electromagnetic wiggler
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Electromagnetic wggler
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Conclusion: One can hardly make Veselago lense based 1D photonic crystal But there are some interesting effects like “electromagnetic snake”, normal channeling, etc.
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