If you are referring to the top (visible face) the pic on the right faces the diode so as to get the lens as close as possible to the diode.
Ideally once the light exits the other end, the fast axis will be almost parallel (not expanding).
The slow axis, will be over corrected and initially converging, only to diverge again within millimetres and start expanding again unless correction optics are used to correct the beam.
Careful.... those look like plastic barrels ...do not use these with high power multi-mode diodes !
Cheers
Last edited by catalanjo; 03-05-2017 at 13:47. Reason: typo