Diffractive beam splitter

Normally, a diffractive beam splitter is used in tandem with a focusing lens so that the output beam array becomes an array of focused spots on a plane at a given distance from the lens, called the "working distance".

This simple optical set-up is used in a variety of high-power laser research and industrial applications that typically include: The theory of operation is based on the wave nature of light and Huygens' Principle (See also Diffraction).

Designing the diffractive pattern for a beam splitter follows the same principle as a diffraction grating, with a repetitive pattern etched on the surface of a substrate.

The depth of the etching pattern is roughly on the order of the wavelength of light in the application, with an adjustment factor related to the substrate's index of refraction.

The etching pattern is composed of "periods" – identical sub-pattern units that repeat cyclically.