[15p-2F-1~15] 4.5 Information Photonics

▲ [15p-2F-5] Reconstruction of complex-amplitude from quantized diffraction patterns by one-shot ptychography

〇Mio Fukui¹ (1.Osaka Univ.)

Keywords:ptychography,diffraction imaging

Ptychography is a coherent diffractive imaging method in x-ray, optical, and electric domains that uses multiple diffraction patterns obtained by the scan of localized illumination on an object. The method enables to retrieve complex-amplitude of the object from the diffraction patterns with a phase retrieval algorithm. Ptychography generally requires a long time to capture necessary diffraction patterns by localizing an illumination probes, which are overlapped with neighbors. Therefore, it is difficult to reconstruct the complex-amplitude of moving objects. To solve the problem, we have proposed a one-shot ptychography capable of capturing a set of diffraction patterns with different defocus and polarization conditions at a time. In the implementation, the intensities of the diffraction patterns are quantized at an image sensor and also degraded by a noise. In this research, we investigated capability in reconstruction of the complex-amplitude and robustness to noises by computer simulation. The assumed optical setup captures four diffraction patterns with different pairs of polarization (horizontal and vertical) and recording positions (in-focus and defocus) by 16-bit image sensors. The complex-amplitude of the object is retrieved from these signals using a ptychographic iterative engine (PIE). Simulation results demonstrate that the complex-amplitude of an object is correctly reconstructed from quantized diffraction patterns. Relationship between the root mean square error and the noise in the capturing process shows that the method is tolerant for about 60 dB noise.