Characterization of Spatial Light Modulator Based on the Phase in Fourier Domain of the Hologram and Its Applications in Coherent Imaging

Huaying Wang,Yunpeng Feng,Feng Fan,Zhao Dong,Yuli Lou,Xianan Jiang

doi:10.3390/app8071146

Abstract

Although digital holography is used widely at present, the information contained in the digital hologram is still underutilized. For example, the phase values of the Fourier spectra of the hologram are seldom used directly. In this paper, we take full advantage of them for characterizing the phase modulation of a spatial light modulator (SLM). Incident plane light beam is divided into two beams, one of which passes the SLM and interferes with the other one. If an image with a single grey scale loads on the SLM, theoretical analysis proves that the phase of the Fourier spectra of the obtained hologram contains the added phase and a constant part relative to the optical distance. By subtracting the phase for the image with the grey scale of 0 from that for the image with other grey scales, the phase modulation can be characterized. Simulative and experimental results validate that the method is effective. The SLM after characterization is successfully used for coherent imaging, which reconfirms that this method is exact in practice. When compared to the traditional method, the new method is much faster and more convenient.

Highlights

Digital holography (DH) is a technology that permits the numerical reconstruction of optical wave fields in both amplitude and phase from a digitally-recorded hologram [1,2,3,4,5,6,7]
Simulative and experimental results can prove that the characterization of phase modulation of Simulative and experimental results can prove that the characterization of phase modulation of the spatial light modulator (SLM), based on the phase in the Fourier domain of the hologram, was effective
This means that, for holography, the reconstructed wave field from a hologram, and the phase in the Fourier domain can be directly utilized in practice

Summary

Introduction

Digital holography (DH) is a technology that permits the numerical reconstruction of optical wave fields in both amplitude and phase from a digitally-recorded hologram [1,2,3,4,5,6,7]. By processing the information contained in a hologram digitally, this technology has been widely used in many fields, including particle field measurements [1,2], structure testing [3,4], and quantitative analysis of cells [5,6,7]. The phase of the Fourier spectra is often processed together with the intensity to get final reconstructed images, and it can be used directly in some applications without reconstruction. Dohet-Eraly et al used the phase in the Fourier domain to achieve numerical autofocusing in DH [8]. We utilize the phase directly for fast characterization of the phase modulation of a spatial light modulator (SLM)

Methods

Results

Conclusion