Fig. 4: The third- and fourth-order spatial differentiation at a wavelength of 638 nm. | Nature Communications

Fig. 4: The third- and fourth-order spatial differentiation at a wavelength of 638 nm.

From: Single planar photonic chip with tailored angular transmission for multiple-order analog spatial differentiator

Fig. 4

a, b Imaging results for the target in the case of the fourth-order (a) and (b) the third-order spatial differentiation. The insets in (a) and (b) show magnified images of the regions marked using a line-box in each case. c, d Intensity profiles measured along the white dashed lines marked in (a) and (b). The grey dashed lines represent the background intensity. e Simulated BFP image at \(\lambda\) = 638 nm, the double arrow-headed line indicates the orientation of the analyzer. The trapezoidal regions are designed to perform the third-order differentiation, and the circular region for the fourth-order differentiation. The vertical and horizontal pink dotted lines indicate the directions of the third-order differentiation, the tilt orange dotted line indicates the fourth-order differentiation. f Experimentally measured BFP image at \(\lambda\) = 638 nm. g, h Intensity profiles along the differentiation directions of the fourth-order (along \(\varphi={45}^{\circ }\)) and the third-order(along \({k}_{y}=-0.16{k}_{0}\)) in (f), together with the corresponding simulated curves, and quartic and cubic fitting curves, respectively.

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