Hi, i recently bought this 50mW Green Laser Diode Module Industrial DIY for Kit - eBay (item 320461204424 end time Jan-10-10 03:12:44 PST)
and the seller says that the beam is "spread out" and at 10 feet, it is 18 mm dot. How do i collimate coherent light? what lens can i use? LInks plz o_0...