The Design Of Diffractive Optical Element And Researches On Photon Transmission In Superlattice

The study of beam modulation and optical transmission properties not only has important scientific significance, but also has important application value in the design of optoelectronic devices. In this thesis, we focus on (i) the theoretical design of diffractive optical elements for beam shaping; (ii) light propagation properties in superlattices with structural defects. Some main results achieved in this thesis are summarized as follows:Using of improved weighted Y-G algorithm, optimization design diffractive phase elements for beam shaping in the fractional Fourier transform domain and laser cavity. By comparing the results of GS algorithm, Y-G algorithm and the weighted Y-G algorithm, we found that the weighted Y-G algorithm can improve the beam shaping effect, reduce the error function and light intensity inhomogeneity, and meliorate the sensitivity of the initial value for general Y-G algorithm and avoid the local maximum. The uniform flat-topped beam after shaping is of the characteristics as high diffraction efficiency, high uniformity, long-distance transmission without distortion and radiation.From the electromagnetic theory of light, we study the transmission characteristic of light waves in superlattice containing generalized SML (GSML (m, n)) defects and quasi-periodic GSML superlattice. A comparison is made when the GSML structure is composed of the right-handed materials, and is composed of the combination of right-handed materials and the left-handed materials. The effects of the orde of GSML structure, optical thickness and incident angle on the optical transmission spectra in these structures have been discussed by using the transfer matrix method. The results show that the band gap is increased while the numbers of GSML structure or the incident angle or the optical thickness is increased, new localized mode emerges. When the GSML structure is composed of the right-handed materials and the left-handed materials, the band gap becomes wider. These results will be useful in the design of the device.