after vs later on

after is an adjective but later on is not an adjective.

Word	Noun	Adjective	Verb	Adverb
after	No	Yes	No	Yes
later on	No	No	No	Yes

As adverbs, after and later on are synonyms defined as:

Other synonyms of after include afterward, afterwards, later, subsequently.

after (adjective)	later on (adjective)
located farther aft

after (adverb)	later on (adverb)
behind or in the rear	happening at a time subsequent to a reference time
happening at a time subsequent to a reference time