Snyder Kaitlynn, Grier David G
Opt Express. 2023 Oct 9;31(21):35200-35207. doi: 10.1364/OE.494593.
Holographic particle characterization treats holographic microscopy of colloidal particles as an inverse problem whose solution yields the diameter, refractive index and three-dimensional position of each particle in the field of view, all with exquisite precision. This rich source of information on the composition and dynamics of colloidal dispersions has created new opportunities for fundamental research in soft-matter physics, statistical physics and physical chemistry, and has been adopted for product development, quality assurance and process control in industrial applications. Aberrations introduced by real-world imaging conditions, however, can degrade performance by causing systematic and correlated errors in the estimated parameters. We identify a previously overlooked source of spherical aberration as a significant source of these errors. Modeling aberration-induced distortions with an operator-based formalism identifies a spatially varying phase factor that approximately compensates for spherical aberration in recorded holograms. Measurements on model colloidal dispersions demonstrate that phase-only aberration compensation greatly improves the accuracy of holographic particle characterization without significantly affecting measurement speed for high-throughput applications.
全息粒子表征将胶体粒子的全息显微镜视为一个反问题，其解决方案能够极其精确地给出视场中每个粒子的直径、折射率和三维位置。这种关于胶体分散体组成和动力学的丰富信息源为软物质物理、统计物理和物理化学的基础研究创造了新机会，并已应用于工业应用中的产品开发、质量保证和过程控制。然而，实际成像条件引入的像差会导致估计参数出现系统且相关的误差，从而降低性能。我们发现了一个此前被忽视的球差源，它是这些误差的重要来源。用基于算子的形式体系对像差引起的畸变进行建模，确定了一个空间变化的相位因子，该因子可近似补偿记录全息图中的球差。对模型胶体分散体的测量表明，仅相位像差补偿可大幅提高全息粒子表征的准确性，且不会显著影响高通量应用的测量速度。
