Dissertation
Dissertation > Mathematical sciences and chemical > Crystallography > Crystal physics > The optical properties of the crystal

Transmission characteristics of electromagnetic waves in the positive , negative refractive index formed Fibonacci Fibonacci quasicrystals

Author WuQingPing
Tutor ZhuKaiCheng
School Central South University
Course Theoretical Physics
Keywords Fibonacci superlattice Negative refractive index Transmission coefficient Defect Imaging
CLC O734
Type Master's thesis
Year 2005
Downloads 146
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Due to the special nature of negative refractive index, negative refractive index has recently become a theme of the research of many scientists. Fibonacci quasicrystals not only unique structure, but also has a peculiar physical properties. In this paper the transfer matrix method, the theory is derived from positive, negative refractive index materials constitute the Fibonacci quasicrystals propagation matrix and the transmission coefficient characteristics. And carefully studied by numerical simulation, when changing the refractive index of the medium, the angle of incidence of the light, under the circumstances of the polarization of the light transmission coefficient. Discussed separately in the coefficient of variation of the transmittance in the case of the different layers by introducing a defect, and further also studied when changing the optical thickness of the defect, the defective material after the transmission coefficient characteristics, and single positive refractive index of the Fibonacci quasicrystals transmission coefficients were compared. Simulated by positive imaging laws of Fibonacci quasicrystals constitute a negative refractive index materials under different conditions, and with the period film compared by analyzing and comparing the following conclusions: (1) light vertically incident cases, When out meet K_Ad_A = K_Bd_B = θ = (k ± 1/2), k = 1.2.3 ... when FC (2n 1) the transmission coefficient has a cyclic nature, the transmission coefficient of the FC (2N) having a switching nature. (2) the introduction of negative refractive index transmission peak position, the width of the transmission peaks, the number of transmission peaks changed significantly. In particular, the band gap can be widened significantly. (3) In the case of S polarization, when the incident angle reaches a certain, band gap completely disappear transmission ratios approximate to 1, which indicates the absence of omnidirectional photonic band gap, and therefore the case of a periodic structure different. But in the case of P polarization, there is a negative refractive index Fibonacci superlattice with omnidirectional bandgap. (4) When the introduction of defects in the Fibonacci superlattice, significantly extends the width of the photonic band gap, and introduction of a defect mode. When defects medium for absorbing medium, and negative refractive index of the absorbing medium, there is a negative refractive index with a single positive refractive index of the the defect mode quasicrystals medium transmission coefficient increases many, or even greater than 1 phenomenon. (5) in the same number of layers and offset the same permeability and dielectric constant, compared Fibonacci sharp peak to peak of the cycle film is constructed in multi-layer film is high, i.e., Fibonacci configuration of the multilayer film structure, compared to the cycle multilayer film can be better suppression of the size of the sharp peak, in a certain extent, can be better near perfect imaging.

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