You can't get a circular beam from it, the best you can do is square. The only way to do this is with correction optics such as an anamorphic prism pair.
Ok thanks for the answer!! And it is not dangerous for my 2w diode 2x battery lc16340 880mhz because is getting very very hot with 2xlc16340 . it's not possible for me to put 1xbattery 18650, my host is too small