Negative refraction in photonic crystals Mike Kaliteevski Durham University
Outine Photonic Crystals: Introduction Negative refraction in left-handed material Non-diffracting beams Electromagnetic wiggler
Bragg reflector r n1n1 n2n2 t
n1n1 r n1n1 d2d2 n2n2
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).
Bragg reflector
Bloch theorem. Dispersion relations
BR = c/(n 1 d 1 +n 2 d 2 ) BR Formation of the photonic band gap in periodic structures
Probability of spontaneous emission
L
Microcavity
Electric field Magnetic field
Probability of spontaneous emission L L
2D Photonic crystal
1D photonic crystal
2D photonic crystal
Dispersion relations in 2D photonic crystal
Plane waves method Bloch theorem Wave equation Lattice vector Reciprocal lattice vector
Plane waves method Wave equation Reciprocal lattice vector
2D photonic crystals HE
Disperison relations H E
Complete PBG
Transmissiom of light Experiment Modelling
PC spectral filter
Defects in photonic crystals m = 1 m = 2 m = 0m = 3
Photonic crystal waveguide
PC Waveguide
OE_15_ D Photonic crystals
Transmission of light and bandstructure in opals and inverse opals.
Photonic microstructures in nature
Negative refraction in left-handed material
Right - hand materials Usual electromagnetic word
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
Refraction KτKτ KτKτ
KτKτ KτKτ Positive refraction
KτKτ KτKτ Negative refraction
Left - hand materials Negative refraction Flat Lense
L n1n1 n2n2 A D Flat lence n1n1 n 2 =-n 1
Superlence ??? Comment: John Michael Williams, Some Problems with Negative Refraction, Phys. Rev. Lett. 87, (2001)Phys. Rev. Lett. 87, (2001) Comment: G. W. 't Hooft, Comment on “Negative Refraction Makes a Perfect Lens”, Phys. Rev. Lett. 87, (2001)Phys. Rev. Lett. 87, (2001) Reply: M. Nieto-Vesperinas and N. Garcia, Nieto- Vesperinas and Garcia Reply:, Phys. Rev. Lett. 91, (2003)Phys. Rev. Lett. 91, (2003) J. B. PendryJ. B. Pendry, Negative Refraction Makes a Perfect Lens, Phys. Rev. Lett. 85, (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”.....
Realization of left-hand materials Metamaterials Photonic crystals
Negative refraction in photonic crystals v gr <0 v gr >0 2D hexagonal metallic PC, D =200 microns, d = 60 microns
Negative refraction in 2D hexagonal photonic crystals
Refraction of wave in photonic crystal prism v gr <0 v gr >0
Refraction of wave in photonic crystal prism
Experimental study of negative refraction
Experimental study of negative refraction of THz using QCL
SIGNAL WITHOUT SAMPLE Negatively refracted beam
Non-diffracting beams W
L l1l1 l2l2 A D n1n1 n2n2 n1n1
Negative refraction in 1D photonic crystals n1 n2 d 1 d 2
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
n1n2 d 1 d 2 x z K 0 Field of the wave in the structure
Modes in Bragg reflector
Amplitude of waves
High contrast: n 1 =3.7 n 2 =1 Low contrast: n 1 =1.4 n 2 =1.8
Negative refraction
Normal channelling
Low contrast: n 1 =1.4 n 2 =1.8 Electromagnetic wiggler
Electromagnetic wggler
Conclusion: One can hardly make Veselago lense based 1D photonic crystal But there are some interesting effects like “electromagnetic snake”, normal channeling, etc.