Paraxial approximation
When we look at light, sometimes we need to do some hard math to understand how it works. The paraxial approximation is a really helpful tool that helps us do this math without getting too complicated.
Imagine a flashlight that's shining on a piece of paper. If we look at the light really close up, we can see that it's made up of tiny rays, kind of like spaghetti noodles. When we use the paraxial approximation, we focus on the noodles that are close to the center of the flashlight beam. We pretend that all the other noodles don't matter and just look at the ones that are most important.
This helps us do some simple math and figure out things like what shape the beam of the flashlight will be or how the light will change if we put a lens in front of it. It's like looking at the big picture of the light and ignoring the tiny details that don't really matter.
Overall, the paraxial approximation is a handy tool that helps us do some useful math when we study light. It's like a shortcut that makes things easier to understand.
Imagine a flashlight that's shining on a piece of paper. If we look at the light really close up, we can see that it's made up of tiny rays, kind of like spaghetti noodles. When we use the paraxial approximation, we focus on the noodles that are close to the center of the flashlight beam. We pretend that all the other noodles don't matter and just look at the ones that are most important.
This helps us do some simple math and figure out things like what shape the beam of the flashlight will be or how the light will change if we put a lens in front of it. It's like looking at the big picture of the light and ignoring the tiny details that don't really matter.
Overall, the paraxial approximation is a handy tool that helps us do some useful math when we study light. It's like a shortcut that makes things easier to understand.