Laser pointer discussion. Read/write reviews of laser pointers and laser pointer companies. Learn about all types of laser pointers and lasers





Welcome to Laser Pointer Forums! If you are looking for a laser pointer or want to compare different laser pointer companies, you may want to check out the LPF Laser Pointer Company Database. The link will open in a new window for your convenience.








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes
Laser Technology Laser Pointer Parts Lasers by Wavelength
Top 10 Laser Pointer Companies Laser Pointer Company Database Visible Beam Laser Pointers


One laser store meets all your needs

























Go Back   Laser Pointer Forums - Discuss Laser Pointers > Lasers > Tutorials, Help & Repairs



LPF List of Laser Pointer Companies (link opens new window)



Reply
 
LinkBack Thread Tools Display Modes
Old 04-20-2011, 10:14 PM #1
hakzaw1's Avatar
Class 4 Laser
 
Join Date: Apr 2009
Location: 'Deep in the Heart Of Texas..."
Posts: 8,333
Rep Power: 24318
hakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond repute
hakzaw1 hakzaw1 is online now
Class 4 Laser
hakzaw1's Avatar
 
Join Date: Apr 2009
Location: 'Deep in the Heart Of Texas..."
Posts: 8,333
Rep Power: 24318
hakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond reputehakzaw1 has a reputation beyond repute
Default Divergence question

Anybody care to translate this for me- maths are not my thing.


assume nothing please.

arctan?? wtf


this equation may as well be in chinese to me.


Laser Beam Divergence = 2 arctan ( (D(f) - D(i)) / 2 L


this ^^^ came from here
Laser Pointer - How to Measure Beam Divergence

so I get the paper and distance part but not much more than that.

Please do not post if you are not willing to give me the version for Dummies. I am not fluent in algebra.

TY Len


__________________
IF YOU ARE NEW HERE- READ ALL THIS http://laserpointerforums.com/f37/an...ml#post1353314
& Spend some hours reading at LASERPOINTERSAFETY.COM

powered by PANGOLIN-ILDA Member since 2014.

QS/FB3 +Beyond-APC40-Mamba Black(clone) 5paghettix2 and I-show x2-Kasio synth-midi
KGB- 532 1.1W 445 2.2W 655 1.3W DT Pro 40 still needs more red.
KGB1W+ 532 DT Pro 40 soon to be GB.
Laserking 1300RGB FULL COLOR 30K(may be FS)
Laserking RGB LK PD2 500 and LK SD 850
REKE RGB 500- G 300
HeNes-(12)R(3)G-COH-594/5 mW-thnx DrSam
MULTILINE-147mW[
445nm 180mW-Mini spiro-Yob.
LPMs-RadiantAlpha& Pro5W-AixiZ SPER/KenmeterLite/LB1
Spacelas 1178mW 655nm/AixiZ 300mW532&
2 B&W 473nm 5/6mW lab
JETLRS1.3W&1.2W-MGL-H
638 180mW ttl mimi lab (av. 230mW)
405 100mW ttl mini lab
445 300 mW ttl mni lab ^AixiZ^ all for a lumia PJ
*MightyMite 2000* RGB all diode 2.2W 30K- 637/520./450...NEW!!
Guide DIY Pjs by Dan-
http://nqlasers.com/scannerreference/index.php?title=Main_Page
hakzaw1 is online now   Reply With Quote







LPF List of Laser Pointer Companies (link opens new window)







Old 04-20-2011, 10:27 PM #2
Trevor's Avatar
Class 3B Laser
 
Join Date: Jul 2009
Location: Boulder, CO
Posts: 4,506
Rep Power: 2565
Trevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond repute
Trevor Trevor is offline
Class 3B Laser
Trevor's Avatar
 
Join Date: Jul 2009
Location: Boulder, CO
Posts: 4,506
Rep Power: 2565
Trevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond reputeTrevor has a reputation beyond repute
Default Re: Divergence question

Divergence Calculator - Safe Lasers - Laser safety information, tools, and free warning labels.

That might help.

-Trevor
__________________
Code:
23:10 <ARG>    nothing has blown up yet :)
23:10 <Trevor> that is a distressingly low standard for success
Trevor is offline   Reply With Quote
Old 05-06-2011, 02:53 PM #3
Class 1 Laser
 
Join Date: Oct 2010
Location: Germany
Posts: 80
Rep Power: 9
donprado has a spectacular aura aboutdonprado has a spectacular aura aboutdonprado has a spectacular aura about
donprado donprado is offline
Class 1 Laser
 
Join Date: Oct 2010
Location: Germany
Posts: 80
Rep Power: 9
donprado has a spectacular aura aboutdonprado has a spectacular aura aboutdonprado has a spectacular aura about
Default Re: Divergence question

I'm not sure if Trevors link already helped - I'll try to explain:

Look at the attached image: green is the laser beam.

The divergence is the full angle between the two green lines.
You measure the diameter of the beam at two positions D(initial) and D(final).
To calculate the divergence, you look at the red triangle: the long side is the distance L between your measurements, the very short side is the difference between the measured radii: D(f)/2 - D(i)/2. The sharp angle of the red triangle is half of the divergence.
There is the formula: tangens(Angle) = Short Side / Long Side, so here we have:

tan (Divergence/2) = ( D(f)/2 - D(i)/2 ) / L = ( D(f)-D(i) )/2L

To get the angle there is the inverse function to tangens: arctan
We do on both sides the same:

arctan ( tan (Divergence/2) ) = arctan ( ( D(f)-D(i) )/2L )

You can skip arctan(tan), so:

Divergence/2 = arctan ( ( D(f)-D(i) )/2L )

Divergence = 2 * arctan ( ( D(f)-D(i) )/2L )

On your pocket calculator, you'll find arctan as 'tan^-1' and you normally can select it by pressing 'INV' followed by 'tan'.

If I look at my post - probably Trevors help was much more useful
Attached Thumbnails
Divergence question-divergence.jpg  
__________________
For every problem, there exists a simple and elegant solution which is absolutely wrong. J. Wagoner
donprado is offline   Reply With Quote
Old 05-06-2011, 03:27 PM #4
RA_pierce's Avatar
Class 3B Laser
 
Join Date: Sep 2007
Location: Southern California
Posts: 3,258
Rep Power: 3873
RA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond repute
RA_pierce RA_pierce is online now
Class 3B Laser
RA_pierce's Avatar
 
Join Date: Sep 2007
Location: Southern California
Posts: 3,258
Rep Power: 3873
RA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond reputeRA_pierce has a reputation beyond repute
Default Re: Divergence question

I'll try to help you out, hak...

First, you will need some known values.
  • Beam diameter at the point of beam termination in meters (call this d2)
  • Beam diameter at the aperture in meters (call this d1)
  • The distance at which you are measuring in meters (call this m)

Note that 1mm is equivalent to 0.001 meters, 2mm is 0.002m, 10mm is 0.01m, etc.
We will call divergence, the answer we are looking for, "D."
Now, to calculate divergence, use this formula:

D = [1000 (d2-d1)] / m

That is, Divergence is equal to (d2 minus d1) multiplied by 1000 and then divided by m.
This will give you approximately the divergence of your laser in mRad.

Does that make sense?

The same formula can be used to calculate the beam diameter at any given distance if you isolate "d2" on one side of the equation.
The algebra is really not that difficult to derive the formula. I'm not great with numbers either, but I managed!
Hope it helps.

Last edited by RA_pierce; 05-06-2011 at 03:37 PM.
RA_pierce is online now   Reply With Quote
Old 05-06-2011, 04:13 PM #5
Bluefan's Avatar
Class 3R Laser
 
Join Date: Aug 2009
Location: The Netherlands
Posts: 1,482
Rep Power: 62
Bluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond repute
Bluefan Bluefan is offline
Class 3R Laser
Bluefan's Avatar
 
Join Date: Aug 2009
Location: The Netherlands
Posts: 1,482
Rep Power: 62
Bluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond reputeBluefan has a reputation beyond repute
Default Re: Divergence question

For small angles that would work, for larger angles the arctan is needed and for precision you'd need the gaussian beam propagation (assuming the beam is gaussian) because the beam diameter around the beam waist is not a nice straight line.

Let the beam diverge far bigger then the initial spot. The divergence is then:
D = 1000 * d/m
With D the divergence in milliradians, d the diameter of the spot and m the distance. This would actually work better then subtracting the initial beam diameter because that is where the beam waist lies not on the cone made by the beam.

Last edited by Bluefan; 05-06-2011 at 04:14 PM.
Bluefan 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











Loading








Green Laser Pointers by Category Blue Laser Pointers by Category Red Laser Pointers by Category
Yellow Laser Pointers by Category Violet Laser Pointers by Category Orange Laser Pointers by Category
Top Laser Pointers by Power - 1 Watt+ Top Laser Pointers by Power - 500mW+ Top Laser Pointers by Power - 250mW+
Laser Pointer Database High Power Laser Pointers Laser Pointer Diodes






Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 05:15 AM.


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