[Laser] Tx lens diameter.

[Richard Burrows]

Hi
Does anybody have thoughts on the merits or otherwise of using  large diameter Tx lens for laser cloud bounce.My initial belief being that above say 1inch dia. for a collimator lens if used with a laser diodeno advantage woul be gained.However If you consider the lens as an antenna then using a 6inch dia. lens should increase the intensity (ant. gain). 
True or not?
When using a white led with 6inch lens I get very intense spot, but leds do  have a wider exit angle than a laser diode.So I'm not really convnced I'll get anymore intensity, unless I use several lasers at the focal point.

I note that the beam expander lens used are larger in dia. than collimator lens placed  before them.

Richard - G8BYI