We present polarization-sensitive Fourier ptychographic microscopy (PS-FPM) capable of generating high-resolution birefringence images of optically anisotropic specimens over a large field of view (FoV). FPM produces high-resolution images of transparent samples over a large FoV based on multiple intensity measurements acquired at various illumination angles and ptychographic phase retrieval. We combine this attractive feature of FPM with a single-input-state illumination and polarizationdiverse imaging system to achieve the imaging of both complex and birefringence information on transparent objects. Compared to conventional polarization imaging techniques, PS-FPM does not involve any mechanical rotation of the polarizer/analyzer and achieves birefringence imaging with a half-pitch resolution of 0.55 μm over 3.78 mm 2 FoV, which corresponds to the spacebandwidth product of 12.5 megapixels. We demonstrate the high-resolution, large-area birefringence imaging capability of PS-FPM by presenting the birefringence images of various anisotropic objects including monosodium urate, Tilia stem, and hemozoin crystals.

Optical anisotropy, which is an intrinsic property of many materials, originates from the structural arrangement of molecular structures, and to date, various polarization-sensitive imaging (PSI) methods have been developed to investigate the nature of anisotropic materials. In particular, the recently developed tomographic PSI technologies enable the investigation of anisotropic materials through volumetric mappings of the anisotropy distribution of these materials. However, these reported methods mostly operate on a single scattering model, and are thus not suitable for three-dimensional (3D) PSI imaging of multiple scattering samples. Here, we present a novel reference-free 3D polarization-sensitive computational imaging technique—polarization-sensitive intensity diffraction tomography (PS-IDT)—that enables the reconstruction of 3D anisotropy distribution of both weakly and multiple scattering specimens from multiple intensity-only measurements. A 3D anisotropic object is illuminated by circularly polarized plane waves at various illumination angles to encode the isotropic and anisotropic structural information into 2D intensity information. These information are then recorded separately through two orthogonal analyzer states, and a 3D Jones matrix is iteratively reconstructed based on the vectorial multi-slice beam propagation model and gradient descent method. We demonstrate the 3D anisotropy imaging capabilities of PS-IDT by presenting 3D anisotropy maps of various samples, including potato starch granules and tardigrade.

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We present polarization-sensitive Fourier ptychographic microscopy (PS-FPM) capable of generating high-resolution birefringence images of optically anisotropic specimens with large field-of-view (FoV). FPM produces high-resolution complex object field of transparent samples over a large-FoV based on multiple intensity measurements acquired with various illumination angles and ptychographic iteration engine. We combine this attractive feature of FPM with single-input-state illumination and pixelated polarized camera to achieve imaging of both complex and birefringence information of transparent objects. Compared to conventional polarization imaging techniques, PS-FPM does not involve any mechanical rotation of polarizer/analyzer and achieves birefringence imaging with a half-pitch resolution of 0.55-μm over 3.78-mm2 FoV, which corresponds to the space-bandwidth product of 12.5 megapixels. We demonstrate high-resolution, large-area birefringence imaging capability of PS-FPM by presenting birefringence images of various anisotropic objects.

Adversarial attacks inject imperceptible noise to images to deteriorate the performance of deep image classification models. However, most of the existing studies consider attacks in the digital (pixel) domain where an image acquired by an image sensor with sampling and quantization is recorded. This paper, for the first time, introduces a scheme for optical adversarial attack, which physically alters the light field information arriving at the image sensor so that the classification model yields misclassification. We modulate the phase of the light in the Fourier domain using a spatial light modulator placed in the photographic system. The operative parameters of the modulator for adversarial attack are obtained by gradient-based optimization to maximize cross-entropy and minimize distortion. Experiments based on both simulation and a real optical system demonstrate the feasibility of the proposed optical attack. We show that our attack can conceal perturbations in the image more effectively than the existing pixel-domain attack. It is also verified that the proposed attack is completely different from common optical aberrations such as spherical aberration, defocus, and astigmatism in terms of both perturbation patterns and classification results.