Optical Frequency Space Interference Studies And Applications Of Electromagnetic Wave Propagation In The Film Structure

The information technology is developed from electronics,optoelectronic to photonics.With the development of the society,the need of information increases greatly.High speed and large capacity are needed by the information technology.In 21th century,the information technology is based on photonics.Nowadays,research and development of material and device are very active.The respond of photonics material is very fast and the structure of photonics material is always film.In this thesis,the spatial interference of the light propagated in the film structure is studied. The results will contribute to the development of advanced photonic materials and devices,and also make progress in photonics technology.The interference effect is one of the most interesting and fundamental phenomena happened in the nature to have been studied for its new feature of the spatial behavior within the quantum limit recently.The mystery of the interference effect not only delays the last words to be written for the subject of the quantum entanglement in the process of one-photon and two-photon interference in the space-time domain,but also challenges our understanding of the interference of the light traveling in the periodic or non-periodic structures.For example,in a homogeneous dielectric film,by summing up all those transmitted or reflected light beams coming out of the film with the phase delay and amplitude change,the total intensity of the light going to the detector can be formulated with respect to the transmission and reflection coefficients that are related to the interference as the function of the incidence angle,optical constant and thickness of the film surrounded by the medium.As regard to the optical matrixes and equations of the thin films that are widely used in the optical field,however,the spatial behavior between neighboring beams has not been taken into account for the film structure.The spatial effect due to the space deviation between neighboring beams could be small and ignored if the film is very thin with the incidence angle in the range to satisfy the condition in which the light interference may consider to occur at the same spatial position in approximation.The micro space between interfered neighboring beams will tend to be increasing for the thicker film or for the highly dense film stack,even more significantly for the two or three dimensional photonic crystals with the internally composed structure in which the micro size will be comparable to the dimension of the wavelength.The limitation of the spatial interference to affect the light propagation in the periodical/non-periodical film structure has not been reported yet.In this work,two SiO₂/Si film samples with different SiO₂ thickness were prepared by the e-beam evaporation method.The ellipsometric data for each sample at certain wavelength were measured at different incidence angles.The results showed that the simulated ellipsometric data reduced from the conventional thin film model deviate greatly from the experimental data.The systematic variation can not be accounted by the experiment error,but may come from the spatial effect on the interference as two beams are not located at the surface position and are apart a bit by a small distance that is the function of the incidence angle.We have analyzed the situation in which the amplitude and phase change with the incidence angle and the thickness.The results show that the spatial effect plays the role that can not be ignored to account for the interference in the film structure.