Degree of diffraction for monochromatic light beams

TL;DR

This paper introduces a quantitative parameter called the degree of diffraction to measure and compare the spreading of monochromatic light beams based on their angular spectrum.

Contribution

It defines the degree of diffraction, enabling quantitative comparison of diffractive spreading of various light beams, extending the concept of the degree of paraxiality.

Findings

The degree of diffraction depends solely on the beam's angular spectrum.

It allows for quantitative comparison of diffractive spreading.

The concept generalizes the degree of paraxiality.

Abstract

A parameter, called the degree of diffraction, is defined to describe the diffractive spreading of a monochromatic light beam. The same as the degree of paraxiality that was introduced by Gawhary and Severini in Opt. Lett. 33, 1360 (2008), the degree of diffraction depends only on beam's angular spectrum. With this definition, it is possible to quantitatively compare the diffractive spreading of different light beams.