Fraunhofer diffraction equation

Imagine you have a big ball, and you throw it against a wall. If the ball hits the wall straight-on, it will bounce straight back to you. But if you throw the ball at an angle or if the wall has a wavy pattern on it, the ball will bounce off in different directions.

This is a bit like what happens when light hits a small obstacle, like a tiny slit or a thin barrier. Instead of bouncing off the obstacle in a straight line, the light waves spread out in different directions. This is called diffraction.

The Fraunhofer diffraction equation is a way to understand how this diffraction happens. It tells us how the waves of light spread out after passing through a small obstacle, like a single slit or a very small hole.

The equation uses lots of mathematical symbols, but it essentially tells us that the pattern of light that we see after diffraction depends on the size and shape of the obstacle, the wavelength of light, and the distance between the obstacle and our eyes or detector.

So, if we shine a laser beam through a small slit and project the pattern onto a screen, we can see the effects of diffraction. The light will spread out in a pattern of bright and dark stripes, called interference fringes, that are determined by the Fraunhofer diffraction equation.

In summary, the Fraunhofer diffraction equation explains how light waves spread out after passing through a small obstacle, like a slit or a hole, and it helps us predict the pattern of light that we will observe after diffraction.