The documented channel

Plotinus → the Arabic Theology of Aristotle (c. 840) → Isaac Israeli → Ibn Gabirol's Fons Vitae (c. 1045) → the Gerona circle and the Bahir's milieu (c. 1180) → the Zohar. Six stations, each attested, each with texts and dates you can go and check.

The reason this wing gets a different word from every other door on the bench. Elsewhere the honest word is rhyme. Here it is descent. The Tree's emanation scheme was inherited, and then made Jewish — most decisively by the node hanging above it.