Download presentation
Presentation is loading. Please wait.
Published byIsaac Barker Modified over 9 years ago
1
Ray Theory of Light n A simple theory of light uses rays as a representation of how light behaves. n This theory is very useful in describing how lenses and mirrors work. n Unfortunately, it is wrong !
2
Wave Theory of Light n A much more accurate theory represents light as a wave motion. n It is much more difficult than ray theory to apply. n We won’t use this theory in this presentation.
3
The most important parameter of a lens is its Focus n This is the point where parallel light rays are converged by the lens
4
Image Formation n An image is formed by the convergence of light rays passing through different parts of the lens
5
How a Lens Magnifies n If an object is close to the focus but not between the focus and the lens, magnification results
6
Infinite magnification ? n If an object is at the focus, it will be infinitely magnified.
7
Divergent rays n If the object is between the focus and the lens, an image cannot form
8
Mirrors are like Lenses n A mirror behaves just like a lens.
9
Apertures n The behaviour of light as it passes through an aperture (a hole) cannot be described by ray theory. n We must use wave theory. n This gives rise to Fresnel optics, Fraunhoffer optics, diffraction theory, interference theory and others.
10
What are all these names ? n They are all the same thing. n A complete theory is called Fourier Optics. n This makes use of the Fourier Transform. n This is easy to apply AND gives the correct answers, not only in optics, but in many branches of science.
11
Want to know More ? n Fourier optics is the subject of another presentation. n You will just have to wait !
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.