# Is the spatial coherence of light a requirement for creating a well-collimated light beam?

I was wondering if, for creating a well collimated light beam, the spatial coherence play a role. In particular, I understand that a laser beam can be well-collimated with respect to light coming from an incoherent source (such as an LED), but it is not clear to me if this is due only to the much lower divergence of the laser beam, or also due to its spatial coherence.

• Spatial coherence and divergence angle are not directly related. A beam with perfect spatial coherence will occupy single transverse mode only (e.g Gaussian beam $\text{TEM}_{00}$) but if the beam waist is too small, it will diverge pretty fast due to diffraction. – wcc Mar 6 at 21:59