Laplacian reconstruction of one single hologram using two dif ferent reconstruction distances or wavelengths

Abstract

A novel numerical algorithm is proposed to reconstruct the Laplacian of an object field from one single in-line hologram. This method uses two different reconstruction distances of z and z+Δz, or two different reconstruction wavelengths of λ and λ+Δλ to reconstruct one digital in-line hologram. Theoretical analysis shows that when the value of Δz or Δλ is sufficiently small, the difference of the two reconstructed fields is an approximation to the second-order Laplacian differentiation of the object wave, and the zero-order and "twin-image" noise can be almost eliminated simultaneously. Computer numerical simulations and optical experiments are carried out to validate the effectiveness of this algorithm. © 2012 Chinese Optics Letter.