A Question About Divergence

[Alpertuner]

Hello everyone,
I want to make an experiment about a divergence of a laser with shining it on to miles away and want to know how big the dot on the surface will be.I'm trying to gain technical information at the moment.
Okay, lets say I have a green laser with 0.9mrad beam divergence and I also have a 10X expander with it.So it is 0.009 mrad beam divergence right?
If I shine this laser to the black wall which is 5km away what will the size of the dot?
How can I calculate it?
0.09mrad means 0.09mm increase in the beam diameter per meters?
I'm so new about this experiments and just want to know about basics.

 

[ELEktron]

Here is the calculator pseudonomen137's JScript Diameter Calculator

 

[Alpertuner]

Here is the calculator pseudonomen137's JScript Diameter Calculator

Thank you.This calculator will do great

 

[Cyparagon]

0.9/10 is 0.09, not 0.009.

Theoretically, that would mean the dot is .09*5000 + original = 46cm or so.

 

[Alpertuner]

0.9/10 is 0.09, not 0.009.

Theoretically, that would mean the dot is .09*5000 + original = 46cm or so.

Hmm 46cm is fair enough.Thank you.

 

[Leodahsan]

I have a question about divergence.

Is the divergence on the laserglow green lasers for real? I mean, 0.14mRad and 0.12mRad is possible? :drool:
You think it have a FAT beam right? They say: 2mm beam @ aperture, 0.14mRad :drool:

Real?

 

[Event_Horizon]

Is the divergence on the laserglow green lasers for real? I mean, 0.14mRad and 0.12mRad is possible? :drool:

Where are you reading this?

 

[Leodahsan]

Here, you click "battery powered" and "Green". The aries and hercules are 0.14mRad and 0.12mRad.

 

[Cyparagon]

That's WITH the optional beam expander in which case the beam would be 2cm at aperture. They're <1.2mrad without.

 

[Leodahsan]

ooh thats the "*" means. Ok thanks.