Abstract

A periodic structural material called grating causes light diffraction. In optics, this property is mainly used for light spectroscopy. In this study, a model of super large period (SLP) grating that can change the shape of light without spectral was proposed and its characteristics were analyzed. In other words, it is a study to implement the shape of a beam using the physical phenomenon of diffraction. This is considered to be another important study in understanding the properties of light and applying it to industry. As a result of this study, it was found that when the grating period of sinusodial Grating, with a surface-relief Grating type was more than 100 μm, it showed the characteristics of the super large period structure. It was found that in such a grating structure, the distribution of diffracted light was linear and showed a pseudo-Gaussian shape as the results of Rigorous coupled-wave analysis (RCWA) simulation. In the SLP grating of 100 μm, only the shape of the beam is changed with the same wavelength of incidence light. The above causes were explained by reconstructing the wavevector based on the grating equation that explains the grating diffraction phenomenon in the super large period condition. This k vector is defined as a value of $k_{zm}=k{\left(1-{\theta }_m^2\right)}^{1/2}$. By defining this k_zm value, it was shown that in the case of white light, the wavelength of the diffracted wave is the same as the incident wave and does not change. This was confirmed by the experimental results of wavelength measurement of the halogen lamp.

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