Low-coherence off-axis digital holographic microscopy

Usually, off-axis digital holographic microscopy requires a coherent light source in order to record a full-field hologram. Nevertheless, a LASER-based illumination leads to a non-negligible coherent noise, decreasing then the imaging quality. We hereby report a simple method to reduce the coherent noise contribution using a low-temporal-coherence illumination while maintaining a large interference area. A diffraction grating is hence introduced in the reference arm of the interferometer, allowing the coherence plane of the reference beam to be tilted following angular dispersion. The phase planes of the reference beam and the object beam appears to be coplanar. The principle and performance of low-coherence off-axis digital holographic microscopy are demonstrated. The three-dimensional reconstruction of a biological sample is performed.