Reference-free off-axis phase ghost imaging based on binary amplitude modulation

Ghost imaging (GI) is a technique that correlates the light illuminating the object with the detected intensity of a single pixel to reconstruct an image of the object. However, conventional GI still relies on complex configurations in phase imaging, such as phase modulation or additional reference light. Here, a reference-free off-axis phase imaging technique based on GI is proposed. By using a point detector to detect a higher-order diffracted intensity in a Fourier plane and using a binary amplitude light field modulated by a digital micromirror device (DMD), the statistical correlation between them constitutes an off-axis hologram. Furthermore, there is no zeroth-order image in the hologram. Then, the object’s complex amplitude is reconstructed by filtering one twin image in the frequency domain. In this technique, the point detector’s aperture size needs to be small enough to reconstruct the object’s phase. The impact of the aperture size is analyzed, and a recommended detector aperture size is provided. This method simplifies the setup of GI in phase imaging, particularly by eliminating the reliance on phase modulation and additional reference light. Leveraging the advantages of single-pixel detection, DMD, and reference-free setup, this technique may be beneficial to advancing fast and stable phase ghost imaging applications.