Periodically patterned columnar thin films as Blazed gratings

TL;DR

This paper demonstrates the fabrication of periodically patterned columnar thin films that function as blazed diffraction gratings with high efficiency, achieved through controlled vapor deposition on lithographically patterned substrates.

Contribution

It introduces a novel method to create blazed gratings using PP-CTFs with controlled growth to form prismatic air cavities, enhancing diffraction efficiency.

Findings

Diffraction efficiencies up to 52% in transmission.

Asymmetric diffraction patterns observed.

Scalar diffraction theory qualitatively explains results.

Abstract

Periodically patterned columnar thin films (PP-CTFs) were made by evaporating CaF2 and directing the vapor flux obliquely towards lithographically fabricated micrometer/sub-micrometer gratings. The growth of the PP-CTFs was controlled by the deposition rate to form prismatic air cavities within them and they function like blazed diffraction gratings with asymmetric diffraction patterns and diffraction efficiencies upto 52% in transmission at visible wavelengths. Scalar diffraction theory qualitatively explained the measured diffraction efficiencies.