Diffraction Grating: Many Slits, Sharper Maxima

Theory

A grating with $N$ equally spaced slits keeps the maxima at $d\sin \theta =m\lambda$ (the same as two slits), but each maximum becomes **$N$ times narrower** and much brighter. That is why gratings separate wavelengths so well in spectrometers.

What to observe

• Compare with the double slit: the beams leaving the barrier are narrower and better defined.

Try this

• Switch to Average intensity.
• Change the number of slits from 2 to 5 and watch the orders sharpen.

Also available in: Rede de difração: muitas fendas, máximos mais nítidos (Português) · Red de difracción: muchas rendijas, máximos más nítidos (Español)