Adjustable Focus Beam expander

[aijii]

Hey guys,

If i wanted to build an adjustable beam expander, similar to the one hb-laser offers, that i could place in a laser beam to use to adjust the end divergence of the beam, what type of lenses would i need ? I would want it to say, shrink the beam from 1x to 0.1x the size, to offer a 1x - 10x the beam divergence ?

Cheers,

Adrian

[aijii]

hey guys,

anyone have any info to help here?

have a look at this link, we want to construct something like the first product on that page. not sure what type of lenses we would require.

[Pangolin]

Why not just buy HB's? I think that, for professionals who can afford to spend the money, there is no substitude for just buying an existing product from a well-established company with a good reputation that already works. You don't have to build everything yourself you know .

Bill

[aijii]

Fair point, and I am waiting on pricing information back on that part from HB.

However I still want to understand the magic around lens selection etc, for what I'd have thought is such a simple application it seems awfully hard to find information about it

[eyceage]

I think a beam expander is basically just a telescope but used backwards, and the focusability comes from being able to change the distance between the objective and subjective lenses.

In this case, a large biconvex subjective and a small biconvex objective, with focal point between them.

An achromatic lens system would be more complex but the same idea.

I'm just guessing so please feel free to correct me.

[ajohnson30]

Well, if http://www.newport.com/OpticalAssist...mExpander.aspx is an accurate representation, the simplest version is just a concave & convex lens pair