Numerical evaluation of diffractive optical elements with binary subwavelength structures

摘要

The diffraction characteristics of diffractive optical elements with binary subwave-length structures are evaluated by the use of FDTD method. An approach for designing binary diffractive lenses with localized subwave-length structures is discussed. The field patterns are computed for several grating parameters. The transmitted fields are analyzed in terms of the effective refractive indices, which are determined by the duty ratio and grating period. We show that the optical diffractive optical elements with binary subwave-length structures work as optical lenses and examine its performance.