Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



Collimating two-knob lasers with 10x expanders.

lasermore

Member
Joined
Mar 2, 2019
Messages
32
Points
8
I know this will end up being a dumb question, but when you buy a laser from
jetlasers.org, what is the best way to dial/tune the two knobs to make the beam
as small as possible at large distances (half a mile, e.g.)? There are two knobs when
you buy a laser with a 10x expander. [My first (certainly/probably wrong) thought was to just
dial both knobs all the way to the left; actually I know that is wrong at this point.]
"Collimate" might not even be the right word here; if so, sorry about that.
 
Last edited:



Encap

Well-known member
Joined
May 14, 2011
Messages
5,242
Points
113
Turn the focus collars/rings and explore/experience what they do and don't do is the best way to learn what they do.

From the JetLasers web site:
"The beam expander does exactly what the name implies - it expands the beam. Because of the limitations of using only one focusing mechanism on any focusable laser, if you want to add versatility and the ability to focus the beam at multiple distances, a beam expander will help you do that.

When you attach the beam expander to the laser unit, you can either diverge the beam or converge the beam at longer distances.

Using the focusing ring on the beam expander (the ring with ridges on it), you can control the focal length of the beam. Also note that the focusing ring on the laser unit itself also affects the focus of the beam expander - they work in conjunction with each other. The focusing ring on the beam expander can be rotated from one end to the other of a total of 13 full rotations so don’t be surprised if you can seemingly rotate the focusing ring on and on."
from: https://www.jetlasers.org/index.php?id_product=15&controller=product
 

lasermore

Member
Joined
Mar 2, 2019
Messages
32
Points
8
That's a great answer. I was kinda wondering if there is a very-systematic way to do it. It's
a two-dimensional search (two knobs), which could seemingly take a long time without some
systematic method. (If there were only one knob, it would be cakewalk, of course.)
 

steve001

Well-known member
Joined
Jun 3, 2007
Messages
2,353
Points
113
I know this will end up being a dumb question, but when you buy a laser from
jetlasers.org, what is the best way to dial/tune the two knobs to make the beam
as small as possible at large distances (half a mile, e.g.)? There are two knobs when
you buy a laser with a 10x expander. [My first (certainly/probably wrong) thought was to just
dial both knobs all the way to the left; actually I know that is wrong at this point.]
"Collimate" might not even be the right word here; if so, sorry about that.
There's only one answer. Assuming you want the beam expander to work as intended the beam from the laser must first be collimated for minimum divergence. Now attach the beam expander then twist the adjustment ring until you achieve minimum divergence. Minimum divergence is known as infinite conjugate.
 

lasermore

Member
Joined
Mar 2, 2019
Messages
32
Points
8
There's only one answer. Assuming you want the beam expander to work as intended the beam from the laser must first be collimated for minimum divergence. Now attach the beam expander then twist the adjustment ring until you achieve minimum divergence. Minimum divergence is known as infinite conjugate.
Great thanks. I didn't know the first knob could be adjusted completely independent of the 2nd knob (in the way you described). Will try that on one of mine that needs tightening-up of the beam.
 




Top