Direct Fourier-plane imaging with enhanced depth of field via cross-phase modulation

Optical imaging plays a critical role in various fields, such as biomedical imaging, remote sensing, and environmental monitoring, enabling high-resolution, non-contact, and multidimensional data acquisition. However, many advanced imaging techniques face challenges, including complex optical setups and stringent calibration requirements. In this work, we propose an optical imaging method that combines the simplicity of the classical 4f system with cross-phase modulation applied to the illumination source, enabling direct spectral-domain imaging. By increasing the phase-strength parameter, we improve the system's depth of field and reduce its sensitivity to longitudinal deviations. We further demonstrate that by reducing the coherence of the illumination source, the proposed system effectively suppresses coherent artifacts and enhances image quality. Experimental results are in excellent agreement with theoretical predictions, validating the effectiveness and robustness of our approach. This method offers some perspectives for optical sensing and detection applications.