One-shot dual-wavelength in-line digital holographic microscopy

In this work, we propose a dual-wavelength in-line digital holographic microscopy (DHM) configuration in order to eliminate the conjugate image and reach the maximum resolution of CCD. By using this configuration, two holograms are acquired in one shot. Our method is based not only on the recordings of two holograms at slightly different planes, but also on the diffraction patterns formed with two wavelengths. With this experimental setup, we are able to analyze fast dynamic processes at the microscopic scale in real time. Theoretical evaluation, computer simulations and experimental results validate our proposal. The experimental results are obtained using a phase-amplitude object and compared with those calculated from the well-established phase-shifting interferometry technique. As far as we know, in-axis configuration with a single exposure has not been used in DHM, as we present in this paper.

► We show in-line digital holograms at each of two wavelengths in a single exposure.
► Dual-wavelength in-line DHM based on a dual-plane intensity measurement is described.
► Neither object nor camera movement is required.
► A single exposure with the on-line configuration resolution is presented.
► The method is suitable for the acquisition of dynamic processes at microscopic scale.