Generation of Color Images by Utilizing a Single Composite Diffractive Optical Element.

Jiazhou Wang,Hui Pang,Axiu Cao,Qiling Deng,Chuntao Xu,Jian Chen,Liwei Liu,Quanquan Mu,Lifang Shi

doi:10.3390/mi9100508

Abstract

This paper presents an approach that is capable of producing a color image using a single composite diffractive optical element (CDOE). In this approach, the imaging function of a DOE and the spectral deflection characteristics of a grating were combined together to obtain a color image at a certain position. The DOE was designed specially to image the red, green, and blue lights at the same distance along an optical axis, and the grating was designed to overlay the images to an off-axis position. We report the details of the design process of the DOE and the grating, and the relationship between the various parameters of the CDOE. Following the design and numerical simulations, a CDOE was fabricated, and imaging experiments were carried out. Both the numerical simulations and the experimental verifications demonstrated a successful operation of this new approach. As a platform based on coaxial illumination and off-axis imaging, this system is featured with simple structures and no cross-talk of the light fields, which has huge potentials in applications such as holographic imaging.

Highlights

A diffractive optical element (DOE) is a phase modulation element that has the potential to significantly promote the miniaturization, integration, and arrangement of conventional optical systems [1,2,3,4,5,6]
DOEs play a key role in the field of holographic imaging [7,8]
In order to address this issue, previous studies were conducted to generate color images using one single DOE, which relied on coaxial imaging and coaxial illumination [9,10,11,12,13,14,15,16,17] or coaxial imaging and off-axis illumination [18,19,20]

Summary

Introduction

A diffractive optical element (DOE) is a phase modulation element that has the potential to significantly promote the miniaturization, integration, and arrangement of conventional optical systems [1,2,3,4,5,6]. In coaxial imaging and coaxial illumination, the phase modulations of incident lights with different wavelengths are obtained by properly designing DOEs. Bengtsson proposed an algorithm that can produce a specific image of two wavelengths at a certain distance [9,10,11]. A DOE was designed for the green light in order to obtain a phase distribution of φG(x, y). A grating phase φT(x, y) was designed and superimposed on φG(x, y) to alter the positions of the three light fields, whose periods determined the values of the DRG and DGB. The parameters determining DRG and DGB, the corrections of chromatic aberrations, and the interactions between φG and φT were analyzed in detail in order to obtain the final amplitude distribution A(x, y). The impacts of the zero-level positions and its optimization measures were considered carefully

Determination of the Parameters DRG and DGB

Interaction Mechanism between Modulation Phase φG and Grating Phase φT