new to lasers - have a basic optics question

[m60gunner29]

I'm new to this whole laser hobby thing so im sure this will sound like a noob question.... thats ok.

So lets say I have a laser pointer. I aim it at the wall a few feet away and the dot is say 3mm in diameter. Well what if I wanted to make the beam say 2 inches in diameter but not that i want a cone shaped beam, but I want the beam still collimated but 2 inches in diameter.

I thought at first what I was looking for was called a beam expander but after research it looks like beam expanders reduce divergance not expand the beam.

i dont want to reduce divergance, i want to make the beam 2 inches around when it exits the laser body and fly across the room still at 2 inches in diameter.

surely there is some really basic lab optic that will do that right?

 

[Ieon]

I'm new to this whole laser hobby thing so im sure this will sound like a noob question.... thats ok.

So lets say I have a laser pointer. I aim it at the wall a few feet away and the dot is say 3mm in diameter. Well what if I wanted to make the beam say 2 inches in diameter but not that i want a cone shaped beam, but I want the beam still collimated but 2 inches in diameter.

I thought at first what I was looking for was called a beam expander but after research it looks like beam expanders reduce divergance not expand the beam.

i dont want to reduce divergance, i want to make the beam 2 inches around when it exits the laser body and fly across the room still at 2 inches in diameter.

surely there is some really basic lab optic that will do that right?

Shining a laser through a magnifying glass will make it diverage like mad say after the focal point it gets really big.

I dunno know to make it 2 inchs and then just diverage a little proberly SOME optic SOMEWHERE on the internet is for that.

 

[Switch]

A beam expander is what you want. It will increase the diameter of the beam , decreasing divergence, which is not a bad thing unless you purposely want it to have worse divergence.

 

[SuicideKing]

i dont want to reduce divergance, i want to make the beam 2 inches around when it exits the laser body and fly across the room still at 2 inches in diameter.

If you want a 2" inch beam, the first thing to start looking for is a 2" inch lens.
http://www.might.com.cn/cn/main.asp?NID=232&listType=4&pid=190

 

[m60gunner29]

If you want a 2" inch beam, the first thing to start looking for is a 2" inch lens.


exactly what i was looking for.... thanks