The difference between single mode laser and multimode laser

The difference between single mode laser and multimode laser

The beam quality of a single-mode laser is good, and the spot is round.
But many wavelengths of laser can not do TEM00.
Especially high-power lasers, multiple LD-synthesized lasers, they are multimode lasers.

Got to CivilLaser.com find more single mode laser and multimode laser.