I haven't been able to find much information about this, maybe I'm searching the wrong thing but, how would you diffuse a laser beam from a thing collimated beam, into a "cone" of light? More directional than an LED, but much more spread out than a laser. Thanks in advance.
It is not clear whether you want to simply spread the beam, or want to diffuse the beam. If you spread the beam, you will end up with a relatively smooth distribution of light. If you diffuse the beam, you will end up with a speckle pattern.
To spread a thin collimated beam into a smooth conical distribution, the best way is to send the beam through a low-power (long focal length) lens and place a pinhole aperture at the focal point. The pinhole aperture will "scrape off" the noise in the beam and produce a smooth distribution.
To diffuse the beam, you can send the beam through, e.g., a ground glass diffuser or an opal glass diffuser; or you could bounce the beam off of a white-painted surface. This will cause the beam to scatter in a wide range of directions, and you can place an aperture downstream to limit the beam to a cone of angles.
If you diffuse a very thin beam, you will end up with large widely spaced speckles in the conical beam. If you first spread the beam to, say, 1/4 inch wide using a lens, then diffuse the beam, you will end up with small closely packed speckles.