Parallel three-step phase-shifting digital holography

Abstract

We propose parallel three-step phase-shifting digital holography as a technique capable of noiseless instantaneous measurement of three-dimensional objects based on phase-shifting interferometry. The proposed digital holography carries out three-step phase shifting at the same time by using a phase-shifting array device located in the reference beam. The array device has a periodic three-step phase distribution, and its configuration is simplified compared with that required for conventional parallel phase-shifting digital holography. Therefore the optical system of the proposed parallel phase-shifting digital holography is more suitable for the realization of the proposed holography. We conduct both a numerical simulation and a preliminary experiment. The results of the simulation and experiment agree well with those of the conventional phase-shifting method and are superior to the results obtained by conventional digital holography by using the Fresnel transform alone. Thus the effectiveness of the proposed technique is verified.

Single-shot digital holography by use of the fractional Talbot effect

“…In the first approach, three interferograms with the same size of the original one, I(x,y,0), I(x,y,π/2), and I(x,y,π) are generated by extracting the values of the original interferogram periodically at locations with the same phase shift, and using linear interpolation to allocate the empty pixels. Interpolation is performed by averaging the values of adjacent pixels in a similar way as is done in Refs [24][25][26]. Note that the interpolation is more accurate for the interferogram with a π/2 shift, as we have information in two pixels of the unit cell.…”

“…To allow time-resolved measurement, several single-shot phase-shifting techniques have been introduced [21][22][23][24][25][26][27]. The point is the simultaneous acquisition of several interferograms at the expense of a loss in the spatial resolution.…”

“…The point is the simultaneous acquisition of several interferograms at the expense of a loss in the spatial resolution. In one approach, specific diffractive optical elements are designed to separate the different interferograms in different spatial regions of the image sensor [25]. Phase-shifting is performed through polarizing elements.…”

“…However, the method requires using pixelated polarizer devices, such as retarder wave plates or linear polarizers, which are difficult to fabricate and hard to integrate with the CCD sensor, and may require relay optical systems introducing undesirable aberrations. Nevertheless, these methods have been used with success to record digital holograms using three and even two phase shifting steps [24][25][26][27]. Finally, other techniques have been proposed that are able to deal with vibrations and to work with moving objects based on computational post-processing [28] or for specific applications such as pattern recognition [29].…”

Two Step on-axis Digital Holography Using Dual-channel Mach-Zehnder Interferometer and Matched Filter Algorithm

“…Recently, pixelated optical components have been used [18][19][20][21][22]. These approaches can directly record phase-shifted holograms with specially designed components.…”