Reducing beam size?

[hybridz0rz]

What lense combination would i use to reduce the size of a beam and still not lose to focusing abilies.
This is a lab laser so any lense combo would work.

Note: I'm not planning or throwing out 100 usd for lenses like this. I'm Looking for something cheap yet reasonable quality and would have some sort of mounting option.

I have been searching around and all i can find is industrial CO2 laser lenses and stuff.

 

[pschlosser]

I worked for a company that manufactured optics for various industries. I learned a great deal about optics during my tenure there. I was a thin film coater and applied coatings to optics. Some things I learned about light and beam diameter is that when light waves are parallel emitting from a point source, the fewer the optics you run the beam through, the tighter the beam.

Once you start washing parallel emissions (light) through optics, you lose some of the benefits a nice tight beam gives you, and introduce the need for focal length. If the focal length between the optic and the target remains constant, this isn't a problem. But it's less ideal for light-show applications.

I coated optics made of Germanium metal. A dull grey metal that absorbs visible light, but transmits (is transparent to) infrared light (IR). I see these often in surplus, but have never bothered to pick any up, since I have a substantial collection of Ge objects at home. You might look around on the net. They have limited application outside of IR light use, so the demand may be pretty low, driving the prices down.

This link to a simple Germanium optic explains the benefits of this metal quite well and succinctly.

Germanium Optical Windows

I hope this information is helpful.

 

[Bionic-Badger]

Talk to Hakzaw1 about some beam expanders. They also work in reverse as beam reducers. The optics are from JetLasers, but at a very good price. Most beam expanders will cost at least $100, but he has some for about $50 or so.

Note that beam expanders are not focusing type optics. They'll take a parallel beam and produce a parallel beam. Also remember that the smaller the beam size, the greater the divergence, which means over long distances the beam size will grow larger faster. The reason people use beam expanders is to reduce divergences over longer distances.

 

[weeba2kv]

useless to even reply on this question

 

[Cyparagon]

You can use a <$5 chinese monocular if you're not too worried about power loss.