Laser, Optics, Physics, STEM, Light.
subtended by the light source at the plane of the slit can be approximated as l/D, and we represent it by θ. Let lₛ = λ/θ — (5) The quantity lₛ = λ/θ is known as the lateral coherence width of the given light source. It depends inversely on θ and thus, decreases with the length of the source.