The Diffraction of Light - Explanation
- Light shone through a narrow slit will diffract and sometimes produce a diffraction pattern.
- To observe a light diffraction pattern, you need to use a light source that is monochromatic
- Monochromatic: A light source that is all of the same wavelength (or frequency).
- If non-monochromatic light is used, then the different wavelengths will diffract by different amounts and the pattern produced won't be very clear.
- White light is made up of a continous range of wavelengths across the visible light spectrum.
- You can put a colour filter in front of white light to make it a single wavelength, but using a laser gives clearer diffraction patterns
- Lasers are monochromatic but also dangerous enough that they could damage your eyesight if looked at directly.
- The diffraction of light is shown by shining a laser beam through a very narrow slit onto a screen.
- You can alter the amount of diffraction by changing the width of the slit.
- If the wavelength of a light wave is roughly similar to the size of the slit, you get a diffraction pattern of light and dark fringes.
1 of 3
The Diffraction of Light - Diagram
2 of 3
Diffraction through Gaps
The amount of diffraction depends on the wavelength of the wave compared with the size of the gap:
- When the gap is much bigger than the wavelength, diffraction is unnoticeable.
- You get noticeable diffraction through a gap several wavelengths wide.
- The most diffraction is when the gap is the same size as the wavelength
- If the gap is smaller than the wavelength, the waves are mostly reflected back.
3 of 3