Girl captivating girl with the dancing beams (5,6)

'beams' is the definition.
(lights in a night club)

'girl captivating girl with the dancing' is the wordplay.
'girl' becomes 'lass' (lass is a kind of girl).
'captivating' indicates putting letters inside (I've seen this in other clues).
'with' says to put letters next to each other.
'dancing' indicates an anagram.
'girl' after 'the' is 'thegirl'.
'thegirl' is an anagram of 'erlight'.
'lass' placed around 'erlight' is 'LASER LIGHTS'.