Optical

	Laser	LED
Radiative medium, specificity?	Identical medium with radiative transitions	Identical medium with radiative transitions
Cavity	Yes	No
Coherence length	from `cm` to `km`	< `cm`
Linewidth	from `nm` to `pm`	a few `10nm`
Preferred type of emission	Stimulated	Spontaneous
Threshold presence	Yes	No
Quantum efficiency	`2*10^-2`	`2*10^-3`