Second Harmonic Generation Of Antiferromagnetic Sandwich Structure In Vertical External Field

Nonlinear transfer matrix method has been used to study the antiferromagneticsandwich structure(middle, for the antiferromagnetic layer for non magnetic dielectriclayer) under a vertical type(external magnetic field direction and antiferromagneticanisotropic shaft are vertical) on both sides of the second harmonic generation. Thestudy found the sandwich structure can enhance the second harmonic output powereffectively near the ferromagnetic resonance frequency, and the selection of themagnetic dielectric layer impacts on the second harmonic output hugely due to thetypical anti ferromagnetic response frequency is in the THz band. Therefore, thisdissertation tries to explore a new possible direction on the ferromagnetic materials inthe THz technology application field.Main conclusions are as follows:The Sandwich structure can enhance the second harmonic output power effectively,the dielectric layer sort of the second harmonic output can generate a significant effect,it appears the non reciprocity of the second harmonic output when the sandwichstructure is non-mirror symmetry,analyzing the generating cause of the none reciprocityin the antiferromagnetic sandwich structure. The coating properties of the SiO2layercan be obtained and the properties of ZrO2are with negative film in the circumstance ofthe FeF2/ZrO2/SiO2system, which enhance the nonlinear effect, on the contrary, if thesequence was inverted, the effect would be getting weaker. Meanwhile, with theincreasing of the antiferromagnetic layer thickness, the second harmonic output powershows a periodic oscillation damping, the cycle is about half of the wavelength.It is found that the ionic crystal can make a further effort in increasing the secondharmonic output of the antiferromagnetic sandwich structure, the harmonic outputpower of the SiO2/FeF2TlBr system is nearly one thousand times of the bare film, tentimes of the ZrO2/SiO2/FeF2system, and the ion TlBr crystal can increase membrane.If we use precious metals Au or Ag layer as the bottom structure, we found that cangreatly enhance the second harmonic output power at the top of sandwich structure,especially the second harmonic output at the top of the SiO2/FeF2/Ag system is five thousand times of SiO2/FeF2/ZrO2system, but there exists a weakness that the secondharmonic output at the top of the system is relatively weak when the incident angle issmall.With the substituting SiO2for ion TlBr, the existing weakness of that the secondharmonic output is relatively weak when the incident angle is small can be improvedeffectively.