Atomi DIY beam expander

[gcsutherland]

So I picked up a universal cell phone camera lens pack and thought I might try my hand at making a proof of concept beam expander. To my surprise everything in that pack worked to make one and no outside materials were used.

<http://imgur.com/FAcv9sg>
<http://imgur.com/tyXQdqJ>
http://imgur.com/tIaokvL
http://imgur.com/T2Po9ZX

Thought I would share for people that like to tinker.

 

[gozert]

Edit: Nvm, for some reason the links aren't working properly.

 

[Alaskan]

Here you go

 

[gcsutherland]

Here you go

Thank you very much. I have been working and haven't had time to come and fix that. I'm going to try a combo of this and a telephoto lens for a keplerian expander with a relay.

 

[Alaskan]

Are the lenses glass in that or plastic? If plastic, no damage? The way I expand my beam is to de-focus the lens on my pointers so it puts out a wide beam, adjusting it so the size of the spot it makes is close to the same diameter of a PCX or plano-convex lens when it is held away at its focal length. That way I don't need to use an expander lens and can adjust the spot size to match what ever PCX lens I am using with it to collimate the beam.

 

[gcsutherland]

Are the lenses glass in that or plastic? If plastic, no damage? The way I expand my beam is to de-focus the lens on my pointers so it puts out a wide beam, adjusting it so the size of the spot it makes is close to the same diameter of a PCX or plano-convex lens when it is held away at its focal length. That way I don't need to use an expander lens and can adjust the spot size to match what ever PCX lens I am using with it to collimate the beam.

I am pretty sure all but one of the lenses are glass. This really was just a silly quick throw together project with no math calculations for focal lengths or lens spacing. There is some beam clipping in my design but it almost makes the oclaro 700 diode a perfect circle.

 

[micheal rosen]

Looks nice! What type of expansion ratio are you getting? You can figure out by dividing the focal length of one lens by the other (larger focal length over small).

I've been thinking of buying some lenses from the surplus shed and making a BE, but I don't know how I'd mount them. I'd probably have to get a mount machined.

 

[gcsutherland]

Looks nice! What type of expansion ratio are you getting? You can figure out by dividing the focal length of one lens by the other (larger focal length over small).

I've been thinking of buying some lenses from the surplus shed and making a BE, but I don't know how I'd mount them. I'd probably have to get a mount machined.

Well I haven't gotten around to measuring the focal length of the biconcave lens since I didn't have pins to cast a shadow and draw a line and blah blah but the plano convex is 4mm focal length. I am waiting for my other lenses to come in the mail at the moment to make a more usable beam expander this one is stationary focus and more of a novelty than anything, that being said it still was fun making. It does expand the beam atleast and makes the terrible "line" of the oclaro diode turn into a dot. This was more unintentional but the output lens does clip some of the beam and makes it almost completely circular. I have this on the wayhttp://www.amazon.com/Telephoto-Manual-Telescope-Camera-Telescopic/dp/B0083QY2JS and some other plano convex and biconcave lenses to interchange inside this "host" to see what success I can get. I feel the forum is in need of a cheap BE.

 

[micheal rosen]

Well I haven't gotten around to measuring the focal length of the biconcave lens since I didn't have pins to cast a shadow and draw a line and blah blah but the plano convex is 4mm focal length. I am waiting for my other lenses to come in the mail at the moment to make a more usable beam expander this one is stationary focus and more of a novelty than anything, that being said it still was fun making. It does expand the beam atleast and makes the terrible "line" of the oclaro diode turn into a dot. This was more unintentional but the output lens does clip some of the beam and makes it almost completely circular.

Wow, that's incredible. My oclaro with an S1 lens has a divergence of like 13mRad or more, it's crazy how much of a line it makes.

 

[gcsutherland]

Wow, that's incredible. My oclaro with an S1 lens has a divergence of like 13mRad or more, it's crazy how much of a line it makes.

I think it is a combination of the black coating on one of the lenses and internal reflection that produces the circle.

 

[micheal rosen]

I think it is a combination of the black coating on one of the lenses and internal reflection that produces the circle.

Could be. How far can it goes before becoming and obvious line again? Or is it to far for you to test? Cause that sure would be nice...

 

[gcsutherland]

Could be. How far can it goes before becoming and obvious line again? Or is it to far for you to test? Cause that sure would be nice...

It never really becomes an obvious line from the distance I have seen it becomes more or less a squarish circle at about 30 feet. The strange phenomenon I have been wondering about is the beam coming out of the expander seems to be split in half with two square beams on top of one another idk if you can see that in the picture.

 

[gcsutherland]

Alright the optics I ordered arrived and I must say that this 12x telephoto lens does really work well at reducing the divergence I will post numbers in a little while, but the output is greatly reduced. I will try to remove the third lens inside to see if that helps but as a cheap beam expander I feel I am on the right path.

 

[CDBEAM777]

Wow, that's incredible. My oclaro with an S1 lens has a divergence of like 13mRad or more, it's crazy how much of a line it makes.

Hmmmm...If you want to correct the output of you Oclarro 63193....give it a set of glasses....as was done with the Dragon's Head build....which again...uses a set of 6X cylindrical lenses...to correct the beam nasty divergence !! ( See link in my sig )

A beam expander expands both the X and Y axis. at the same time. So....a beam expander will also reduce the divergence of the nasty Oclarro LD !!

But...a cylindrical lenses expand one axis only...and by expansion....yes, expansion of the beam slow axis....yes, slow axis, the divergence of a astigmatic beam is corrected.

At the end of the day....the goal is to correct the beam....so that the X axis divergence....is as close to being equal to that of the Y axis divergence... and a simple set of Cylindrical lenses will do this job....much more efficiently.....and therefore....much, much less power loss....like under 5%

And...B4 a student of optics points out...the correction is not perfect...but much, much improved....yes !

I post this....not to dissuade any experiments/tinkering with optics....for that is how we learn and have fun. I have just started to experiment with the amazing optics of Beam Expanders....and they are amazing.....but....I post to be helpful and share what small amount of knowledge I have acquired....with a great amount of experimenting and tinkering ! I hope the post projects that feeling of sharing and not a dismissive tone !!!

Beam out

 

[gcsutherland]

Hmmmm...If you want to correct the output of you Oclarro 63193....give it a set of glasses....as was done with the Dragon's Head build....which again...uses a set of 6X cylindrical lenses...to correct the beam nasty divergence !! ( See link in my sig )

A beam expander expands both the X and Y axis. at the same time. So....a beam expander will also reduce the divergence of the nasty Oclarro LD !!

But...a cylindrical lenses expand one axis only...and by expansion....yes, expansion of the beam slow axis....yes, slow axis, the divergence of a astigmatic beam is corrected.

At the end of the day....the goal is to correct the beam....so that the X axis divergence....is as close to being equal to that of the Y axis divergence... and a simple set of Cylindrical lenses will do this job....much more efficiently.....and therefore....much, much less power loss....like under 5%

And...B4 a student of optics points out...the correction is not perfect...but much, much improved....yes !

I post this....not to dissuade any experiments/tinkering with optics....for that is how we learn and have fun. I have just started to experiment with the amazing optics of Beam Expanders....and they are amazing.....but....I post to be helpful and share what small amount of knowledge I have acquired....with a great amount of experimenting and tinkering ! I hope the post projects that feeling of sharing and not a dismissive tone !!!

Beam out

Thank you for your reply I have studied your posts and followed them for some time now and yes you are right. I guess my main point of this was to give people a project and a cheap alternative for a beam expander. I took apart the telephoto lens and had to take two plano-convex and one big convex lens out as well as the prism and reverse mounted the output plano-convex while also adding a biconcave I had from the first beam expander to the input and presto I have a beam expander and it really works I'll get some pics and measurements now.

 

[gcsutherland]

So at 31 feet with 3 element lenses we get a "dot" of 50mm. With the beam expander we get a more perfect dot of 20mm.

Can't take a picture of the dot with calipers in frame since I have to hold the beam expander in place.