Chunguang Meng | Searcharxiv

arXiv2026

Generalized Optics-Free Cross-Correlation Ghost Imaging via Holographic Projection with Grayscale and Binary Amplitude-only Computer-Generated Holograms

In certain applications or wavelength regimes, essential optical components for imaging systems are either unavailable or challenging to fabricate. To address this, we propose an optics-free classical ghost imaging (GI) scheme utilizing visible light. By employing grayscale and 0-1 binary amplitude-only computer-generated holograms (CGHs), generated via a modified Gerchberg-Saxton algorithm combined with Otsu's thresholding method, we achieve accurate replication of light intensity distributions with central symmetry in the holographic projection plane. Experimentally, we first optimized system parameters by analyzing the point spread function (PSF) and subsequently demonstrated cross-correlation GI through the precise replication of dynamic speckle patterns. Furthermore, by incorporating sparse target patterns, we significantly enhanced the imaging quality. Given the high-speed modulation capabilities of digital micromirror devices (DMDs) for 0-1 binary amplitude-only CGHs, the proposed scheme represents a significant advancement toward practical implementation, particularly in the X-ray regime where conventional optics are difficult to employ.

physics.optics↗

arXiv2025

Active control of the peak value of the Hanbury Brown-Twiss effect using coherent light by lensless holographic projection

Computer-generated holography enables projection of target patterns onto designated planes, providing deterministic control over the probability density function of the projected light intensity. Here, we introduce an active control scheme for the peak value of the Hanbury Brown--Twiss effect, $g^{(2)}(0)$, utilizing lensless holographic projection with coherent light. Notably, single-frame holographic projection yields a markedly different $g^{(2)}(0)$ from its multiframe-averaged counterpart due to the presence of coherent speckle noise. With the coherent speckle noise suppression, we derive an analytical expression $g^{(2)}(0)$ on holographic projection plane, revealing that it is determined by the target coherence length, its statistics, and the numerical aperture of projection system. Our experimental results show good agreement with the theoretical analysis, confirming the joint influence of these factors. By employing dynamic sparse target patterns, we achieve a maximum $g^{(2)}(0)$ of $39.77$. Numerical simulations, benchmarked against experimental measurements, reveal that coherent speckle noise enhances $g^{(2)}(0)$ through mutual superposition with the target pattern, leading to a joint modulation of intensity fluctuations. In summary, by manipulating multiple controllable parameters, we establish a robust strategy for tailoring $g^{(2)}(0)$, paving the way for advanced applications in speckle imaging and optical metrology.

physics.optics↗