Light Diffraction From a Flexible Patterned Layer With Periodically Arranged Dimples

Abstract

Patterns with periodically arranged dimples are fabricated by an inexpensive soft-imprint lithography technique on a flexible transparent polymer substrate. Excellent diffraction characteristics, with highly intense and fine features, are seen from these polymer layers in transmission, even though the effective refractive index variation across their thickness is very small. The diffraction is studied at two different feature sizes and at multiple wavelengths. The results from the experiment emphasize that the diffraction is a 2-D spatial Fourier transform of the object but with some important limitations. Numerical calculation based on rigorous coupled-wave analysis exactly reproduces the results and supports the features of the experiment such as unequal intensity distribution in the diffraction pattern.

Keywords

• Diffraction
• soft-imprint lithography
• metasurface
• bidirectional scattering distribution function (BSDF)