Focus on green modules...?

[jupiter8]

Question - I'm not that happy with the divergence on my DL Viper 95mW pointer. I suspect they set the focal length short for burning ability, which results in a divergent beam over a longer distance (?). I actually had a go at refocusing it, only to discover that the collimating lens was glued precariously onto the focusing ring - of course it dropped out, and I spent about an hour cleaning it and carefully gluing it back into position. (I work in laboratories and have a steady hand and a lot of patience).
So I'm back exactly where I started from with this laser.

I've decided to buy a green module, about the same power (approx. 100-150mW) but if possible I'd like to have an adjustable focus ring. Here's the dilemma; all 532nm modules I've been looking at for sale don't appear to be focusable - to my untrained eye in any case. Is this true? All I want to be able to do is fine tune the focus for the lowest divergence I can manage and leave it set at that. Any suggestions?

For instance THIS module from o-like - focusable?

 

[LarryDFW]

jupiter8;

It is difficult to focus the green laser modules because of the long F.L. final lenses.

I just put a similar new 125mw module in my 18650 housing and was faced with same question.

After playing with the final focus lens repeatedly, I looked for a less-time-consuming method.

The solution I came up with was:

1. Leaving the beam collimated to infinity.

2. Adding a quality AR lens with a removable silicone rubber cap for burning at close range (about $12).

Now the laser can accomplish both purposes.

LarryDFW

 

[HIMNL9]

There is one possible solution (other than the one i already tried, dismantling an o-like module and turning it focusable ) ..... i'm planning something about this, from months, but it need a lot of machines work, and i don't have access to machines, so til now is all in "paper draws" stage .....

Basically, as you know, a DPSS output coupler (the two lenses after the crystal) is a poor level beam expander ..... so i thoughd ..... why don't made a green host that includes a "better beam expander" ? :evil:

This requires to dismantle an existing module, taking away the front lens and the threaded tube, without touch anything other ..... then, need to thread the inside of the "heatsink/head" with the same diameter and thread of the removed tube, but more long ..... then make a lens holder (basically a threaded tube on the external, that can hold a lens inside), and place in it a bigger lens, with a longer FL .....

When you screw in the back part of the module on the botom of the head, and the lens holder on the top, you have a focusing system that can act as a beam expander ..... not professional, and for sure not a "10X" or similar, but at least the double of the standard of the normal focusing system, with the bonus that is focusable ..... and if you find a negative lens to place just in front of the expander, also more .....

Ofcourse, this give you a "fat" beam at the output of the assembly, but this is common, with the expanders, after all .....

 

[jupiter8]

HIMNL9 - that's brilliant! Keep us posted. It doesn't need to be anywhere near 10X, you'd get a very fat beam with that setup anyway. Even something equivalent to 2X optically built into the module with nice quality lenses would be a vast improvement, do you think? If you have the machining facilities to try this I might consider paying you for your time, if you're interested in supplying me with one...

 

[jupiter8]

Now I can't decide which one to buy... can anyone recommend an optically good green module at a reasonable price. I am happy with around 100mW, 150 max. One that I can tweak the focus of myself would be perfect, otherwise divergence of <1.0mRad would be preferable...

 

[HIMNL9]

Unfortunately, i don't have, at the moment, access to any machine, this is the reason for which some of my projects are stopped at half, or also at paper draw plans level, til now .....

I'm trying to find a cheap mini-lathe too, but here in Italy the prices are simply absurds, compared to the ones in the USA or other countries .....

If i find the way for put my hands on a machine and do some practical work, i'll let you know, but can be a long waiting, seen my actual work situation ..... sorry .....