![https://www.youtube.com/watch?v=atg1PN1sZfg](https://www.youtube.com/watch?v=atg1PN1sZfg)

Diffraction  is a property of all waves and something that happens when a wave hits an object or passes through an aperture. 
This applies to waves in a pond, sound waves, or light waves 
- this gives CDs their amazing shiny culture 
- as  well as opals their textured shine 
- as well as atoms and molecules  
- the reason why nearby stars also have their distinct patterns

A program for diffraction --> [DiffractSim](https://github.com/rafael-fuente/diffractsim?tab=readme-ov-file)

# Arago Spot 




# Frenel Zone Plate



When you shine light through a series of lines it becomes a working diffraction grating. 

Adding more diffraction gratings adds more spikes. Diffraction comes from distance between the lines and the angle. 



# Spatial Light Modulator 
Instead of controlling RGB values like a normal screen, each pixel instead adjusts its index of refraction. 

Refractive index - a measure of how much light slows down when it enters that material 

the higher refractive index, the more light is slowed relative to light in a vacuum.