Feature

Wavelength Compensation of Broadband Light Diffraction

P. Andrés, Dept. Óptica, Universidad de Valencia, Burjassot, Spain; V. Climent, J. Lancis, E. Tajahuerce, M. Fernández-Alonso, and G. Mínguez, Dept. Ciencias Experimentales, Universitat Jaume I, Castelló, Spain.

Propagation of electromagnetic waves in free space is a physical phenomenon that explicitly depends on the wavelength of the light radiation. This fact results in the chromatic dispersion of the optical field diffracted by an aperture illuminated with a broadband source. The above situation severely restricts the spectral bandwidth of the illumating source that can be used in a diffraction-based optical system. If our interest is that all the spectral components produce the same effect, broad-band-dipersion compensation is then required. The milestone of the compensation procedure lies in achieving the incoherent superposition of the monochromatic versions of a selected diffraction pattern in a single plane, with the same scale for all the wavelengths of the incident light. Achromatic diffraction systems meet the above requirement in a first-order approximation.