Beam Comparision of a NUBM44 Laser Pointer With and Without a Beam Expander

This is not a video, it just shows a photo of the size difference between the spot created by a NUBM44 laser diode pointer with and without expansion, or expander. The wide stripe is produced by a standard 6.33 mm diameter collimation lens such as the G2, the small spot produced by a beam which has been expanded to about 2 inches wide, without cylinder pair correction.

Adding a beam expander, or lens with a long enough focal length to allow the beam to expand before collimation, the result is a much lower divergence beam. For example, the NUGM44 diode has a divergence above 12 mRad when using a standard 6.33 mm diameter lens with a short focal length. Put a large diameter lens with a 2 or 3 inch focal length in front of the diode instead of the small lens, and the beam will be much wider leaving the pointer, but also have a proportionally lower amount of divergence producing a much smaller beamwidth or spot in the distance.

The photo on the left side is of the spot on a roof top from an expanded beam about 2 inches wide, the photo on the right side is the spot on the same roof top from a pointer which used a standard 6.3 mm diameter lens such as the G2.