Diffraction of transmission light through triangular apertures in array of retro-reflective micro-prisms

TL;DR

This paper investigates the diffraction patterns produced by triangular apertures in micro-prism arrays, linking pattern features to fabrication imperfections and geometrical parameters through experimental and theoretical analysis.

Contribution

It introduces a model of micro-prism arrays as multi-period blazed gratings and interprets diffraction patterns based on interference and array theorem, including effects of fabrication imperfections.

Findings

Hexagram-shaped diffraction patterns explained by interference.

Relation between diffraction fringes and array imperfections established.

Geometrical parameters like dihedral angle measured via diffraction features.

Abstract

The array of micro-prisms was described by model of multi-period blazed gratings consisting of triangular apertures. The origins of hexagram-shaped diffraction patterns were interpreted based on multiple-beam interference and diffraction array theorem. The relation between zonal /line ghost fringes and imperfectly fabricated array structures was analyzed. Geometrical performances (e.g., the dihedral angle of micro-prism) were tested by measuring the features of diffraction patterns of samples from three retro-reflective sheeting manufacturers.