Carter, DeLuca & Farrell LLP
Fourier lens, method for designing Fourier lens, and schlieren apparatus
Provided are a Fourier lens, a method for designing a Fourier lens, and a schlieren apparatus. The Fourier lens includes a substrate and a plurality of cuboid waveguides. The plurality of waveguides are arranged on the substrate in parallel and spaced from each other at a preset interval. The material of the substrate and the material of the waveguides are all transparent to the working waveband of the Fourier lens. The preset interval is smaller than a quotient obtained by dividing a center wavelength of the working waveband by the refractive index of the substrate. The waveguide has a plurality of widths, and the waveguides of different widths correspond to different phase delays. The individual waveguides are arranged on the substrate according to phase delays required at different positions. According to the embodiments, the range of the working angle of the Fourier lens can be increased.
NANKAI UNIVERSITY
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Shuqi Hua Wenwei Jianguo
Chen Cheng Liu Tian