Slit Diffraction Spectrum Manipulation in Non-Paraxial Regions via the Spatial-Spectral Correspondence Relationship

Abstract

In the past, a two-dimensional aperture diffraction of light in the non-paraxial region could only be studied using the Huygens integral without functional forms. This work presents a special case—a one dimension slit where the functional form can be obtained. The monochromatic light intensity distributions are investigated in detail. Using the correspondence relationship, the diffracted spectra of polychromatic light in that region can be readily found. Three interesting spectral effects are described: spectral switches, multi-level data transmission, and optical wavelength ruler. Since the functional form is derived without approximation, it is applicable to a region very near to the slit, including the wavelength region or even sub-wavelength scale. Thus, for light with micron-order wavelength (visible to near infrared (NIR) band), these results are valuable to micro- or nano-optics, especially for studies of the spatial intensities or spectral characteristics in the non-paraxial region.