50mm FL Lens?

[Wolfman29]

How is everyone fitting these in builds with the new 5W reds? To get it to focus to infinity, you would need to have it be 5cm (2 inches) away from the diode. Your lens would need to be huge. How is everyone doing this? Why can't we use a shorter FL lens? I realize that we won't get as nice a beam, but the power loss would be massive from a 50mm FL lens, right? I mean, unless it's as big as the beam is wide =p

Answers would be awesome! Need it for my phaser build.

 

[shokkunlasers]

You can't use short FL lenses because its a FACed diode.

I would ask Lazeerer about how wide the beam is at 50mm.

Also the Lens Lazeerer used for his build with this diode is availalbe in different diameters and slightly shorter FL

Thorlabs - N-BK7 Plano-Convex Lenses (AR Coating: 350 - 700 nm) :beer:

 

[Wolfman29]

Jesus. Half an inch in diameter at the smallest. Thanks for the link. I'm not too good with optics. Never been my strong suit.

 

[BShanahan14rulz]

Why can't you use the usual shorter FL aspherics? Is just the overall divergence would be high or something?

If you don't care about beam symmetry or fast axis divergence, what about removing the FAC?

http://i944.photobucket.com/albums/ad289/Laseerer/650 power diode 5W/P6020036_zps751d2a36.jpg < according to this pic (and I don't know if this is the same lens you folks are talking about or not), it looks like a majority of the beam hits the lens.

 

[Wolfman29]

I guess a 50mm lens wouldn't be too bad. Just not sure if there is room in my phaser!