Détaché in the lower half uses a free upper-arm movement, swinging back on the down-bow and forward on the up-bow.
When combined with string crossing the upper-arm stroke must include the vertical component of the string-crossing action.
Détaché in the lower half is best used at slow or medium tempos.
Notice that Fintan uses the side of the bow hair to reduce bow friction in this heavier part of the bow....
