Beam widening on pen laser

Hi all,

I have a 5mW green pen laser where the beam has gotten wider. Instead of a tiny point, the beam point is about 2.5cm wide at three feet.

How can I fix this to make the beam tighter?

P.S. I know next to nothing about laser pointers. Need some "help for dummies"

That means that divergence is big.

First you need try to focus it.

If that doesn't help you need to change optics.
You can use collimating lens with longer Focal Length and that should fix problem with divergence but beam will be fatter at aperture.

ok wait, "try focusing it" that doesn't really help. That's like someone asking " I need to get a message to a friend in china" and you respond, "oh simple, just build a telephone" dude, if he (or I) knew ANYTHING about how we go about that, do you really think we would be asking??? and google doesn't help at ALL!! anytime you even type the word "laser" in ANY sentance, you just get a shitload of advertisements trying to pedal cheap wayyyyy under spec lasers. Please help, but step by step instructions, we BEG you.

OK...

By moving lens further or closer from diode you change focus.
If you move lens further from diode than focus point will be closer to aperture and vice versa.
What you want is to achieve infinite focus.

What you should do...

You should screw in or screw out lens and watch beam.
Watch if you can achieve smaller dot than before.
If you can that is great. But if you cannot than you should replace that lens with lens that has longer focal length.

When lens has longer focal length that means that lens need to be placed further from diode (or crystal or other optical element) in order to achieve focus to infinity.

If lens is further from crystal that will make beam fatter but will also help to achieve better divergence.

Take a look on this thread...

http://laserpointerforums.com/f49/how-make-beam-fatter-50905.html

That is what you should do.