DL beam expander

[gregorio87]

I have bought a laser beam expander from DL.
It is come to me with a part unmount, the custom has unscrewed it (I think to see if into there is any kind of drugs or illegal substance to import), but I have mount the part, and it work great.
At night, vith my Viper, I can set the beam with a divergence of 0,12 mRad, and it looks like a real straight line.
It has three grains (see first pic) to block the two mobile parts, when you have found the correct position that you want.
I'm afraid because we can't use it with our DIY module, because the max beam input is only 2,5 mm,
I don't know if this feature can be changed making a more big hole in the tail of the beam expander.
I want to make another part like this with a turning machine, but with a biggest hole.

Gregorio

 

[gregorio87]

Its components...

 

[gregorio87]

It mounted on my Viper laser, the Viper appear very small...

 

[gregorio87]

Some shoot indoor.

 

[steve001]

You've got to use it outside. Shine it on a distant target showing examples of what adjusting the lens does to the spot size. Showing the beam indoors looks like any other beam photo indoors

 

[gregorio87]

Yes, I know, but I have make the pics in daytime. In the night I have to do somethings. When I'll have time I'll make some pics outdoor in the night, and then I'll post here.


Gregorio

 

[davidgdg]

I didn't spot the locking nuts and couldn't figure out why it was so stiff to adjust. A kindly watchmaker next door pointed them out! Duuuh.

I'm going to try to measure divergence with the expander as soon as I get back tonight. 0.12mrad sounds incredible!

 

[Benm]

You can get great divergences with optics, but the beam will be bigger too.

I've tried using quality 10x50 binoculars, those can make good beam expanders but are very finicky to handle in combination with a laser pointer.

I'm afraid because we can't use it with our DIY module, because the max beam input is only 2,5 mm,
I don't know if this feature can be changed making a more big hole in the tail of the beam expander.

I reckon that is limited by the output lens too. If you want to expand a 5mm thick beam 10 times, you obviously need a 50 mm output lens to make it happen.

 

[davidgdg]

Divergence measurements on Viper 125

With beam expander

When screwed all the way so that the distant spot is as small as possible:

Spot at aperture: 1mm
Spot at 6.67 metres: oval 3*5mm

Divergence mean of 3mm over 6.67metres= 0.4mrad

Without beam expander:

Spot at aperture: 1 mm
Spot at 6.67 metres: oval 6*7mm

Divergence mean of 6.5mm over 6.67 metres = 1 mrad

All figures approximate.

Laser is well made with excellent close range burning characteristics due to the very small spot. The expander is not needed for close range burning. Haven't tried longer range burning due to handshake!

 

[lightfoot500]

hi gregorio
what makes you think the custooms opened it,
dont customs attach a note to let you know for sure they inspected it?
thanks,
just curious.

 

[steve001]

Divergence measurements on Viper 125

With beam expander

When screwed all the way so that the distant spot is as small as possible:

Spot at aperture:  1mm
Spot at 6.67 metres: oval 3*5mm

Divergence mean of 3mm over 6.67metres= 0.4mrad

Without beam expander:

Spot at aperture: 1 mm
Spot at 6.67 metres: oval 6*7mm

Divergence mean of 6.5mm over 6.67 metres = 1 mrad

All figures approximate.

Laser is well made with excellent close range burning characteristics due to the very small spot. The expander is not needed for close range burning.  Haven't tried longer range burning due to handshake!

You might want to recheck those figures when using the beam expander. At a distance of 6.67m you may be and probably are still within the Rayleigh Range. Those measurements should start at 10m on out