Dual-Wavelength Digital Holography Based on Phase-Division Multiplexing Using Four Wavelength-Multiplexed Phase-Shifted Holograms and Zeroth-Order Diffraction-Image Suppression

We propose a dual-wavelength phase-shifting digital holography technique with four wavelength-multiplexed holograms based on phase-division multiplexing utilizing the 2π ambiguity and zeroth-order diffraction-image suppression. Zeroth-order wave suppression is implemented by introducing the averaging method. Its effectiveness is experimentally shown and numerically and quantitatively investigated. The numerical investigation demonstrates the tolerance of the proposed technique against incoherent light noise and changes in the reference wave intensity. The image quality in the proposed technique depends on the intensity ratio between the object and reference waves but does not degrade with constant changes in intensity. In contrast, a previously reported four-step dual-wavelength phase-shifting technique was affected by the factors described above.