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

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

how to make a beam thinner?

Joined
Feb 23, 2008
Messages
2,832
Points
48
what optics do i need to reduce the size(width) of the beam and make it thinner(like a laser pointer)
 





Joined
Dec 30, 2007
Messages
573
Points
0
Read this thread here from reply #7 on, where we discuss thinning a fat Pulsar beam and show how with the Optics simulator and actual lenses.

Cheers, CC
 
Joined
Dec 26, 2007
Messages
682
Points
28
Curiously Coherent,
I think this question deserves it own thread, (this one) IMHO.
I would like to have a thinner bean for my Blu-rays. I have read the entire thread that you have refferenced, it seams that there is a lot of good theory, and the "optics simulator" works good, but I do not believe everything that is done in this simulator is the greatest in real-life. For instance, I can achieve anything I want with only 2 lenses in the simulator, but should I actully use more, 3-5-9-? lenses for reason not apparant in the simulator, (scatter, divergance, etc.)? Also, I am not sure what the number in the simulator mean when I try to buy lenses that match my simulation, Focal-lengths, distances in MMs?
If I am not mistaken, the shorter the wave length, the thinner a beam can be with the same divergance. I believe this is why a 532/green-beam, can be so much thinner than a 650/red without horrible divergance, or is this more due to the DPSS vs. Direct-diode?
My reasoning: I want a nice, tight visible beam from my blu-rays, no focusing. Should I be using a set of 532/green lenses for my 405/Violets instead of the 650nm DX modules?
Does anyone have the lense specs for a typical 532nm/green set-up?
Any specific information regarding a practical method of "thinning", not focusing a 405nm beam would be greatly appreciated. ;D
Dark Horse
 
Joined
Jun 3, 2007
Messages
2,560
Points
113
Dark_Horse said:
Curiously Coherent,
I think this question deserves it own thread, (this one) IMHO.
I would like to have a thinner bean for my Blu-rays. I have read the entire thread that you have refferenced, it seams that there is a lot of good theory, and the "optics simulator" works good, but I do not believe everything that is done in this simulator is the greatest in real-life. For instance, I can achieve anything I want with only 2 lenses in the simulator, but should I actully use more, 3-5-9-? lenses for reason not apparant in the simulator, (scatter, divergance, etc.)? Also, I am not sure what the number in the simulator mean when I try to buy lenses that match my simulation, Focal-lengths, distances in MMs?
If I am not mistaken, the shorter the wave length, the thinner a beam can be with the same divergance. I believe this is why a 532/green-beam, can be so much thinner than a 650/red without horrible divergance, or is this more due to the DPSS vs. Direct-diode?
My reasoning: I want a nice, tight visible beam from my blu-rays, no focusing. Should I be using a set of 532/green lenses for my 405/Violets instead of the 650nm DX modules?
Does anyone have the lense specs for a typical 532nm/green set-up?
Any specific information regarding a practical method of "thinning", not focusing a 405nm beam would be greatly appreciated. ;D
Dark Horse

There's no way around it. A thin beam will have higher divergence the opposite for a wide beam
This applet [use IE to see the graphical presentation] will tell you a lot more than the other lens applet

http://www.lightmachinery.com/gausbeam.php
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=2029
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=2537&search=1
Vis0 Reflectance curve for BBAR lenses
http://www.edmundoptics.com/images/catalog/7067.gif

if you get stumped by the applet pm me and we'll try and set up a time so i can walk you through it.
 
Joined
Dec 26, 2007
Messages
682
Points
28
Steve001,
Great info, thank you.
I am not looking for 0-rad divergance, just something like a 532nm/green, but in an easily availble package. I can already acheive what I am looking for on my bench, just not in a host. I am thinking of just sacrificing a cheap DX 532nm 5mW pen, ($16), and replacing the IR diode with a PS3 diode, and a new driver of course.
Thanks again,
Dark Horse
 
Joined
Jun 3, 2007
Messages
2,560
Points
113
Dark_Horse said:
Steve001,
Great info, thank you.
I am not looking for 0-rad divergance, just something like a 532nm/green, but in an easily availble package. I can already acheive what I am looking for on my bench, just not in a host. I am thinking of just sacrificing a cheap DX 532nm 5mW pen, ($16), and replacing the IR diode with a PS3 diode, and a new driver of course.
Thanks again,
Dark Horse


Now your talking about doing an entirely different project which appears to have little to do with your original questions. You may still need to do what I suggest for best results. Good or superior optics will make all the difference.
0 divergence is not possible
 
Joined
Sep 12, 2007
Messages
712
Points
0
Most of us understand that 0 divergence is not possible, but thinning out the beam doesn't necessarily mean he wants better divergence. I would love to have a 2mm red beam coming out of my laser. I bet the beam would be more visible if it was concentrated like that. the aixiz lens is not the only way to focus a laser; although, currently it the cheapest and easiest way.
 
Joined
Jan 7, 2007
Messages
6,309
Points
83
I found one of my old colliminators for my NdYag.  Adapted it to the S-KY 200...   Now to see what it does.

Mike

OMG what a difference. By all means -- Build one. At 150 yards, the beam went from 8" to about 2" as observed from 150 yards. These work great.
 

Attachments

  • Sky1.jpg
    Sky1.jpg
    8.3 KB · Views: 465
Joined
Dec 26, 2007
Messages
682
Points
28
Most of us understand that 0 divergence is not possible, but thinning out the beam doesn't necessarily mean he wants better divergence. I would love to have a 2mm red beam coming out of my laser. I bet the beam would be more visible if it was concentrated like that. the aixiz lens is not the only way to focus a laser; although, currently it  the cheapest and easiest way.  
Exactly what I was trying to say, Thank you pwnstar. I understand that divergance and beam diameter tend to work against each other. I had used the example of a"0-rad" to illustrate this, but I guess I missed the mark. I want better beam specs from my blu-rays than an Aixiz module can provide, something more like we get from a 532/green laser module, that is all. Let us say a 1.5 - 2 mm dia beam with a 1m/rad diveragance. I know this is achievable, I can do it on my bench, just not yet in a host with easily available module, and yes, the beam is much more visible when condensed.
If you notice a $5 "cat-toy" 3-5mW laser pointer has much better beam specs than our Aixiz/DX modules, except for when it come to focusing to a point. Tiny dot up close, and a reasonable sized dot at reasonable distances, 405nm should be much better at this than either 650nm of 532nm, due to its wavelength, I believe. Focus to a point is great for burners, but I want a 405nm "laser-razor" to play with.
Thank you for all of the info and experience, if I come up with anything usefull, I will post for everyone.
Dark Horse
 
Joined
Jan 11, 2008
Messages
671
Points
0
Hemlock Mike said:
I found one of my old colliminators for my NdYag. Adapted it to the S-KY 200... Now to see what it does.

Mike

OMG what a difference. By all means -- Build one. At 150 yards, the beam went from 8" to about 2" as observed from 150 yards. These work great.

How can you build one? I REALLY want to try this. :D
 
Joined
Jan 7, 2007
Messages
6,309
Points
83
LF -- There's another post on here linking to a place which sells a kit. It is just a diverging lens and a magnifying lens like a telescope. You need to design the focusing arrangement.

Mike
 

Benm

0
Joined
Aug 16, 2007
Messages
7,896
Points
113
pwnstar said:
I would love to have a 2mm red beam coming out of my laser. I bet the beam would be more visible if it was concentrated like that. the aixiz lens is not the only way to focus a laser; although, currently it  the cheapest and easiest way.

I guess the obvious way to do that is to use a stronger lens closer to the laser diode. This would result in a thinner beam coming out of the laser, but with larger divergence yielding a bigger dot a long distances.

The issue is that the laser diode has to be on the focal point of the lens, and the beam width coming out is just the width of the uncollimated laser diode output at the focal distance. Making lenses with extremely short focal distances is hard however, so eventually you'll have to come up with a solution that uses 2 or 3 lenses.

It's also possible to use a monocular (or one half of a binocular of course) to expand or collimate your beams. Results are a bit variable since they usually work with prisma's to keep things compact, but experimenting with them is interesting.
 
Joined
Jan 7, 2007
Messages
6,309
Points
83
I thought I saw two glass lenses at MI -- A single element and a multi-element.

Mike
 
Joined
Oct 23, 2007
Messages
1,904
Points
0
You cannot have both low divergence and small beam diameter. You must sacrifice one for another, either low divergence with a fatter beam (At aperture), or higher divergence with a thinner beam (At aperture).
 




Top