Subwavelength imaging for overcoming the diffraction limit
Date Issued
2009
Date
2009
Author(s)
You, Yun-Kai
Abstract
In this thesis, imaging properties and principles of lens made by metamaterial and metal are investigated. First of all, for left-handed lens, we investigate optical transfer function and transmission coefficient of left-handed lens and we employ Fourier optics to analyze the imaging characteristics of left-handed lens. The results show that left-handed lens indeed could overcome the diffraction limit by the amplification of the evanescent waves, but resolution will be limited by absorption effect, and the analysis also show that if absorption exist, imaging ability of left-handed lens will be restricted in near field. For metal lens, we analyze the characteristics of imaging in the same way with left-handed lens, we separate the metal imaging system into to part : symmetric and asymmetric structure. The results show that also metal lens could amplify evanescent waves, but both the symmetric and asymmetric structure in metal imaging will produce more noise to reduce imaging quality. In spite of this metal lens still can overcome the diffraction limit to achieve better resolution in near field.
Subjects
metamaterial
left-handed lens
metal lens
optical transfer function
evanescent waves
resolution
diffraction limit
Type
thesis
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