Holography with Incoherent Light

Abstract

Conventional digital holography uses the technique of combining two coherent light fields and the numerical reconstruction of the recorded hologram leads to the object amplitude and phase information. Despite significant developments in the DH with coherent light, complex field imaging with arbitrary coherent sources is also desired for various reasons. Here, we present a possible experimental approach for holography with incoherent light. In the case of incoherent light, the complex spatial coherence function is a measurable quantity and the incoherent object holograms are recorded as the coherence function. Thus, to record complex spatial coherence a square Sagnac radial shearing interferometer is designed with the phase-shifting approach. The five-step phase-shifting method helps to measure the fringe visibility and the corresponding phase, which jointly represents the complex coherence function. The inverse Fourier transform of the complex coherence function helps to retrieve the object information.

Keywords

• digital holography
• interference
• coherence
• phase-shifting