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Study on phase characteristics of subwavelength metallic holes

Phase modulation characteristics of subwavelength metallic square holes are investigated for 2D imaging purpose. Based on Maxwell equations, the transmission model of three-dimension subwavelength metallic holes is founded by a mode expansion technique. The relationship between the widths of the holes and the phase from -π to π is established when the thickness of metallic film is given. Then the influences of coupling electromagnetic (EM) fields as well as the incident angle on phase retardation are investigated and calculated through varying the center distance between double holes. A slab lens is demonstrated by using hole-array formed on a metallic film, which verifies the theoretic analysis.