A couple of great laser lens references. First simple, second in depth.

A couple of great laser lens references. First simple, second in depth.
Scott Thorne The Basic Laser Optics has your beam pattern in it. It is totally normal!

http://www.lasercomponents.com/de/?embedded=1&file=fileadmin/user_upload/home/Datasheets/lc/applikationsreport/lens-theory.pdf&no_cache=1

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&cad=rja&uact=8&ved=0ahUKEwjNnc3Y1MDMAhUU-GMKHdF_BgQQFghBMAg&url=http%3A%2F%2Fwww.springer.com%2Fcda%2Fcontent%2Fdocument%2Fcda_downloaddocument%2F9781849960618-c1.pdf%3FSGWID%3D0-0-45-993418-p173947146&usg=AFQjCNFuMEqMO-Tm5z57qdKq4hU-t_2KqA&sig2=D1e7bJFnzyJOH5TYwylRgQ&bvm=bv.121099550,d.cGc