Initial Laser Beam Input in Zemax

Gkaz4

Greetings to all and all the best wishes for 2012.

I need to model a laser beam (which is supergaussian, top hat profile) with a specified divergence that passes through a rectangular aperture. This beam will then pass through an afocal telescope and ultimately the imaged wavefront will serve as the object for the folowing relay telescopes.

My question is how should i define this beam in Zemax and how can i input my divergence? Do i need to use vignetting factors for this?

I am a not so experienced ZEMAX user and i would really appreciate your answers.

Best regards

S.