A Study On Nonlinear Effects Of Plasma Photonic Crystals

If a structure combines the plasma with nonlinear material, it will produce dispersion,anisotropic and nonlinear. Nonlinear plasma photonic crystals will appear nonlinear phenomena suchas high-order harmonic, bi-stable and four-wave mixing. These characteristics can meet the need ofsome devices and have important engineering application background.In the second part of this paper we derive in detail the finite difference time domain method tomake it suitable for the linear medium and the nonlinear medium. This paper uses the Newtoniteration method and fixed point iteration method to solve nonlinear equations. So the traditional finitedifference time domain method is extended to numerical calculation of nonlinear electromagneticmaterial. And we improve the traditional transfer matrix method, and make it suitable for numericalcalculation of nonlinear medium.In the third part of this paper we study the influence factors of the photonic crystal band. Forexample, the dielectric constant of the medium, the plasma frequency, the plasma collision frequency,plasma-dielectric layer thickness ratio, the number cycles of plasma photonic crystal. Under theresearch of the influence factors of plasma photonic crystals band-gap characteristic, we focus onhigh-order harmonic and bi-stable of nonlinear effects. In the study of high-order harmonic generationand modulation, the photonic crystal structure is composed of linear material and plasma andnonlinear material and plasma. Terahertz frequency range is accord with the requirement of frequencyof plasma, and also meets the scope of nonlinear material nonlinear coefficient. Nonlinear materialswhich can be combined with the characteristics of the plasma photonic crystals produce tunablehigh-order harmonic. We reduce three-order harmonic produced by nonlinear material by increasingthe layer number of photonic crystals, reducing the frequency of plasma. We introduce nonlineardefect to enhance higher harmonic in order to achieve the ultimate goal of higher harmonicmodulation. And the plasma photonic crystal is studied in the modulation phenomenon of bi-stableeffect. We introduce coupled nonlinear defect layers to the PCs in order to control the bi-stableeffect.With un-magnetized plasma combined with nonlinear material as a composite structure defectstructure of photonic crystals, threshold of the bi-stable response decreases nearly300than thresholdof the general nonlinear defect structure. The decrease of the bi-stable threshold is quite important forthe fabrication of isolator, optical switch device.In the fourth part of this paper the microwave devices based on plasma photonic crystals aresimulated and designed, on the basis of high-order harmonic research, we design a frequency multiplier, and the original base wave frequency can be transformed into three times of the frequency.Then we designed a tunable narrow-band band-pass filter, a one-dimensional photonic crystal iscomprised of alternate dielectric layer and vacuum layer. Two quantum wells as defects can beconstructed by sandwiching two plasma slabs symmetrically in the one-dimensional photonic crystal,and a dual-narrowband pass-band filter formed. We will adjust the plasma frequency narrow bandfrequency, and change the two quantum well spacing to adjust the pass band width and the half powerbandwidth.