Adaptive wavelength calibration for robust multi-plane phase retrieval.

Area of Science:

• Optics and Photonics
• Computational Imaging
• Wavefront Sensing

Background:

• Multi-plane phase retrieval reconstructs wavefronts from diffraction patterns.
• Laser instability and calibration errors cause wavelength deviations, leading to phase errors and reduced resolution in phase retrieval.

Purpose of the Study:

• To develop an adaptive wavelength calibration (AWC) algorithm to compensate for experimental wavelength deviations in multi-plane phase retrieval.
• To improve the accuracy and resolution of phase imaging by mitigating cumulative phase errors.

Main Methods:

• Proposed an adaptive wavelength calibration (AWC) algorithm that adjusts axial propagation distances during iterative reconstruction.
• Utilized the wavelength-distance equivalence in Fresnel diffraction to dynamically adjust axial spacing.
• Employed enhanced particle swarm optimization to determine optimal axial corrections and minimize structural similarity differences.

Main Results:

• Achieved sub-nanometer wavelength accuracy even with large deviations.
• Demonstrated robustness against coupled errors from wavelength drift and stage misalignment through experiments.
• Validated the algorithm on resolution targets, phase objects, and biological samples.

Conclusions:

• The AWC algorithm effectively compensates for wavelength deviations in multi-plane phase retrieval.
• This method enables high-fidelity phase imaging, even with low-cost, less stable laser sources.
• The approach relaxes stringent wavelength stability requirements for advanced phase imaging techniques.