Old 09-20-2007, 07:36 AM #1
Class 4 Laser
 
Join Date: May 2007
Location: Queensland, AU
Posts: 7,549
Rep Power: 2560
Things has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond repute
Things Things is offline
Class 4 Laser
 
Join Date: May 2007
Location: Queensland, AU
Posts: 7,549
Rep Power: 2560
Things has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond repute
Default Core's divergence?

hi all, i just wanted to know if anyone has tested the cores divergence, as i had a go at pseudo's calculator, and i got about 0.2Mrad? is this good?
thanks


Things is offline   Reply With Quote


















Old 09-20-2007, 03:15 PM #2
Class 2M Laser
 
Join Date: May 2007
Posts: 534
Rep Power: 13
Aseras is on a distinguished road
Aseras Aseras is offline
Class 2M Laser
 
Join Date: May 2007
Posts: 534
Rep Power: 13
Aseras is on a distinguished road
Default Re: Core's divergence?

it's not .2 mrad..

My core is ~.8 mrad that's about as good as most pointers will get.
Aseras is offline   Reply With Quote
Old 09-20-2007, 10:34 PM #3
Class 4 Laser
 
Join Date: May 2007
Location: Queensland, AU
Posts: 7,549
Rep Power: 2560
Things has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond repute
Things Things is offline
Class 4 Laser
 
Join Date: May 2007
Location: Queensland, AU
Posts: 7,549
Rep Power: 2560
Things has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond repute
Default Re: Core's divergence?

well that's what pseudo's calculator said???maybe i should try again?
Things is offline   Reply With Quote
Old 09-21-2007, 11:58 PM #4
styropyro's Avatar
Class 4 Laser
 
Join Date: Jun 2007
Location: Carbondale, IL
Posts: 5,349
Rep Power: 208972
styropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond repute
styropyro styropyro is online now
Class 4 Laser
styropyro's Avatar
 
Join Date: Jun 2007
Location: Carbondale, IL
Posts: 5,349
Rep Power: 208972
styropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond reputestyropyro has a reputation beyond repute
Default Re: Core's divergence?

I believe it is somewhere around .2 mRad, my old leadlight had amazing divergence (Right now it doesn't work for some reason, I hope I can fix it) it was something like .3 mRad on Pseudo's calculator, I wish my CNI had divergence like my leadlight.
__________________

Always protect your seeing balls!
styropyro is online now   Reply With Quote
Old 09-22-2007, 02:10 AM #5
Class 4 Laser
 
Join Date: May 2007
Location: Queensland, AU
Posts: 7,549
Rep Power: 2560
Things has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond repute
Things Things is offline
Class 4 Laser
 
Join Date: May 2007
Location: Queensland, AU
Posts: 7,549
Rep Power: 2560
Things has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond reputeThings has a reputation beyond repute
Default Re: Core's divergence?

so is higher Mrad better, or lower? hmmm i'm still not sure how accurate the result was???
Things is offline   Reply With Quote
Old 09-22-2007, 03:02 AM #6
Class 2 Laser
 
Join Date: Sep 2007
Posts: 323
Rep Power: 16
Rasel is just really niceRasel is just really niceRasel is just really niceRasel is just really niceRasel is just really nice
Send a message via AIM to Rasel
Rasel Rasel is offline
Class 2 Laser
 
Join Date: Sep 2007
Posts: 323
Rep Power: 16
Rasel is just really niceRasel is just really niceRasel is just really niceRasel is just really niceRasel is just really nice
Send a message via AIM to Rasel
Default Re: Core's divergence?

You want lower. Divergence refers to how fast the beam expands over a distance. To get a good idea, I think if your lasers divergence is "x," you can multiply x times the distance in meters to get the approx. added diameter of the beam in mm.

Ex.
Divergence: 1.2mRad
Initial Beam Diameter: 2mm
Distance: 100m

1.2 * 100 = 120mm

Add the initial beam diameter in and you get a dot size of 122mm ~ 12.2cm
Rasel is offline   Reply With Quote
Old 09-22-2007, 03:03 AM #7
Milos's Avatar
Class 2M Laser
 
Join Date: Apr 2007
Posts: 859
Rep Power: 2307
Milos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond repute
Milos Milos is offline
Class 2M Laser
Milos's Avatar
 
Join Date: Apr 2007
Posts: 859
Rep Power: 2307
Milos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond repute
Default Re: Core's divergence?

You want the mRad number to be as close to zero as possible for beam to stay tight over distance. The higher the number the more it diverges, meaning spreads out over distance. If it is a negative number ( such as WL Pulsar's beam) it will converge first and than continue to spread out.

If divergence, (or better say collimation in this case:-)) is 0mRad (which is physically impossible) the diameter of the beam at the source would be the same over infinite distance.

My two Cores have 0.7mRad which is quite good.
__________________
Stingray-3 "The Hercules Killer"
http://laserpointerforums.com/f52/st...ml#post1132489
Milos is offline   Reply With Quote
Old 09-22-2007, 03:13 AM #8
laserrod's Avatar
Class 2 Laser
 
Join Date: Aug 2007
Location: St Louis
Posts: 341
Rep Power: 97
laserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond repute
Send a message via Yahoo to laserrod
laserrod laserrod is offline
Class 2 Laser
laserrod's Avatar
 
Join Date: Aug 2007
Location: St Louis
Posts: 341
Rep Power: 97
laserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond repute
Send a message via Yahoo to laserrod
Default Re: Core's divergence?

RASEL Ur correct
A good LASER will spec. at *near .8 mRAD which = *A *.8 meter spot size at 1000 meters distance (.0008X1000)

KEYWORD: milliradians ,1/1000 of 57.xx degrees

A collimeter at the LASER output will reduce beam spread by several times.

See member Stevetexas. He has one that cost $550, a M/G. Wish I had one too!

Coll. should have AR coatings(anti reflection) on 1st lens concave and 2nd convex(spread beam then collimate)

LASER beam>----[)--=(]======TARGET

If the beam is polarized circular at first, all the better 8-) 8-)

:-?QUES::: 1. Does anybody know the best way to convert a beam to circular polarization?

I read to pass the LASER through a 1/4 wave plate w/side or inline ......... "I don't understand" I think most Greenies are randomly polarized.
:-?Ques.: 2. Agree?

Cheers ---->*< 8-)
[smiley=beer.gif]

FACT: A focused beam that's circ. pol. won't reflect back to the source w/harm.
laserrod is offline   Reply With Quote
Old 09-22-2007, 05:58 AM #9
Class 1M Laser
 
Join Date: Aug 2007
Posts: 168
Rep Power: 11
Angdvl089 is on a distinguished road
Angdvl089 Angdvl089 is offline
Class 1M Laser
 
Join Date: Aug 2007
Posts: 168
Rep Power: 11
Angdvl089 is on a distinguished road
Default Re: Core's divergence?

Quote:
Originally Posted by Laserrod
RASEL Ur correct
A good LASER will spec. at near .8 mRAD which = A .8 meter spot size at 1000 meters distance (.0008X1000)

KEYWORD: milliradians ,1/1000 of 57.xx degrees

A collimeter at the LASER output will reduce beam spread by several times.

See member Stevetexas. He has one that cost $550, a M/G. Wish I had one too!

Coll. should have AR coatings(anti reflection) on 1st lens concave and 2nd convex(spread beam then collimate)

LASER beam>----[)--=(]======TARGET

If the beam is polarized circular at first, all the better 8-) 8-)

:-?QUES::: 1. Does anybody know the best way to convert a beam to circular polarization?

I read to pass the LASER through a 1/4 wave plate w/side or inline ......... "I don't understand" I think most Greenies are randomly polarized.
:-?Ques.: 2. Agree?

Cheers ---->*< 8-)
[smiley=beer.gif]

FACT: A focused beam that's circ. pol. won't reflect back to the source w/harm.
Laserrod, I always thought this was what a collimator did:

LASER beam>====(]==[)---------TARGET

Doesn't that seem more logical? Wouldn't you want the beam to be more concentrated for burning?
Angdvl089 is offline   Reply With Quote
Old 09-22-2007, 06:21 AM #10
Gazoo's Avatar
Class 3B Laser
 
Join Date: Jun 2007
Location: Dallas Tx
Posts: 3,199
Rep Power: 1335
Gazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond repute
Gazoo Gazoo is offline
Class 3B Laser
Gazoo's Avatar
 
Join Date: Jun 2007
Location: Dallas Tx
Posts: 3,199
Rep Power: 1335
Gazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond reputeGazoo has a reputation beyond repute
Default Re: Core's divergence?

In your diagram the beam would collimate with the first lens and spread with the second one.
Gazoo is offline   Reply With Quote
Old 09-22-2007, 06:30 AM #11
Class 1M Laser
 
Join Date: Aug 2007
Posts: 168
Rep Power: 11
Angdvl089 is on a distinguished road
Angdvl089 Angdvl089 is offline
Class 1M Laser
 
Join Date: Aug 2007
Posts: 168
Rep Power: 11
Angdvl089 is on a distinguished road
Default Re: Core's divergence?

Quote:
Originally Posted by Gazoo
In your diagram the beam would collimate with the first lens and spread with the second one.
Oh yeah :-[

So I guess a collimator can collimate to a bigger and smaller diameter beam?
Angdvl089 is offline   Reply With Quote
Old 09-22-2007, 12:45 PM #12
Milos's Avatar
Class 2M Laser
 
Join Date: Apr 2007
Posts: 859
Rep Power: 2307
Milos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond repute
Milos Milos is offline
Class 2M Laser
Milos's Avatar
 
Join Date: Apr 2007
Posts: 859
Rep Power: 2307
Milos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond reputeMilos has a reputation beyond repute
Default Re: Core's divergence?

collimators first widen the source for easier collimation. Then the lens collimetes it to the better degree.

here is pic of couple pretty big collimators in my stash. White one I build and it outputs about 8mm of Core's beam. Black one is a simple scope finder for telescope and it outputs as low as 0.2mrad of green but the diameter of the beam is close to 10mm.
The more collimator widens the beam first, the better it can collimate it.
Attached Thumbnails
Core's divergence?-img_2957_001.jpg  
__________________
Stingray-3 "The Hercules Killer"
http://laserpointerforums.com/f52/st...ml#post1132489
Milos is offline   Reply With Quote
Old 09-22-2007, 03:10 PM #13
laserrod's Avatar
Class 2 Laser
 
Join Date: Aug 2007
Location: St Louis
Posts: 341
Rep Power: 97
laserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond repute
Send a message via Yahoo to laserrod
laserrod laserrod is offline
Class 2 Laser
laserrod's Avatar
 
Join Date: Aug 2007
Location: St Louis
Posts: 341
Rep Power: 97
laserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond repute
Send a message via Yahoo to laserrod
Default Re: Core's divergence?

Milos,
Well said.

The point I was tring to convey is; if you 1st lens the beam to spead out for a short distance(@lens focal lenth) and then lens it back to parallel, you will acheve a beam that spreads out much less over distance!

I was using my $30 Russian made 20x50 telescope outside this morning with a 100 mW greenie and it seemed to make a real bright sparkly spot on a garage door 4 houses away.

Now to get (this set up) the Coll. beam to light a match at 100 meters!

Member Stevetexas has pioneered this act. Search forum for "match at 300 feet" or somthing.

Good pics., thanks Milos, looks like a homebrew collimater.

[smiley=beer.gif]
laserrod is offline   Reply With Quote
Old 09-22-2007, 03:55 PM #14
Class 2M Laser
 
Join Date: Jun 2007
Posts: 650
Rep Power: 16
chimo is a jewel in the roughchimo is a jewel in the roughchimo is a jewel in the roughchimo is a jewel in the rough
chimo chimo is offline
Class 2M Laser
 
Join Date: Jun 2007
Posts: 650
Rep Power: 16
chimo is a jewel in the roughchimo is a jewel in the roughchimo is a jewel in the roughchimo is a jewel in the rough
Default Re: Core's divergence?

Here's a thread I started a few months ago. Your divergence figure will be more accurate if you use long distances.

http://www.laserpointerforums.com/fo...84011673/all-0
chimo is offline   Reply With Quote
Old 09-22-2007, 04:31 PM #15
laserrod's Avatar
Class 2 Laser
 
Join Date: Aug 2007
Location: St Louis
Posts: 341
Rep Power: 97
laserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond repute
Send a message via Yahoo to laserrod
laserrod laserrod is offline
Class 2 Laser
laserrod's Avatar
 
Join Date: Aug 2007
Location: St Louis
Posts: 341
Rep Power: 97
laserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond repute
Send a message via Yahoo to laserrod
Default Re: Core's divergence?

Here is the bottom line on collimaters:

You use them to reduce your spot size at a distance. otherwise; the spot size would be bigger at a distance.

But we here at LPF want to focus the beam for highest power density!!!
Yes, we need more power density at distance!!
So if we make the beam spot bigger from the get-go, it will end up smaller at the distant target than otherwise. Hope you all are still with me here.
But
Even after expanding the beautiful raw parallel beam with a coll./telescope to a bigger paralel beam to any diameter, then try to focus at target at the coll./telescope we will not be able to get a higher power to area density ratio (burning power) .
So we either:
1. focus the raw laser beam(w/no coll./telescope) at the target location with a lens diam. same as beam waist.( I think this would give highest power but the beam is real big) Thats more volume of air the beam must penitrate??

Or
focus the LASER through a telescope/collimator (will resultin a beam spot smaller than the raw laser beam at distance)with a lens right at the target location.

Remember that we want the higest power density at distance.

Does anyone think this can be done (highest power density)without using a third lens at the distant target?

[smiley=evil.gif]
laserrod is offline   Reply With Quote
Old 09-22-2007, 05:19 PM #16
laserrod's Avatar
Class 2 Laser
 
Join Date: Aug 2007
Location: St Louis
Posts: 341
Rep Power: 97
laserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond repute
Send a message via Yahoo to laserrod
laserrod laserrod is offline
Class 2 Laser
laserrod's Avatar
 
Join Date: Aug 2007
Location: St Louis
Posts: 341
Rep Power: 97
laserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond reputelaserrod has a reputation beyond repute
Send a message via Yahoo to laserrod
Default Re: Core's divergence?

Collimators.

It is really just a telescope with 2 lenses.

You spread the laser beam then you make it parallel again to make the spot smaller at a distant target. Simple right?

Cons. reflected light from the lenses is wasted because it won't hit target. But the result is beam with more circular polarized power.(we want light waves that are perpenticular to the beam axis)
The beam waist is enlarged by the device and the beam won't be as visable as is passes by our field of view. A bigger beam waist means less power density.

Pros;
The device makes the beam behave and more parallel.
The distant target will recieve a higher power density.
You get a brighter spot at target just because it will be smaller than otherwise.

Clear as mudd right? [smiley=lolk.gif]
laserrod is offline   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

























Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 09:33 AM.


Powered by: vBulletin
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC