Who are the L P F optic experts?

[Alaskan]

Who here is good with laser optics, specifically a single PCX cylinder lens used to make a line who might be willing to tackle some questions in PM?

 

[Cyparagon]

I can probably help. Maybe. But why not make your questions public so others can learn something?

 

[lasersbee]

IDK, just thought maybe I'd take it off line.

Yeah... I usually share stuff when I'm sure
about an idea or have something concrete.
Sorry can't help you with this optics inquiry.


Jerry

 

[Cyparagon]

It... might be easier to understand your question if you drew a sketch.

You can collimate only one axis if you like. I'm not sure why you would want to. The other axis will diverge just as it would without collimation. The divergence of the collimated axis depends on the diode's emitting area and final diameter, which depends on the lens.

 

[steve001]

IDK, just thought maybe I'd take it off line. Has anyone taken the output of a laser diode and collimated it with a PCX cylindrical lens and measured the divergence of the lines thickness? Will a larger width cylinder lens with a longer focal length cause the thickness of line to expand less in the distance the same as if using a beam expander, or is all reduction to divergence in the plane opposite of the line lost when turned into a line?

You've not stated which axis. That matters what the answer will be.

 

[Andrew124C41]

That confirms my thinking guys, that's all I wanted. Thank you.

E: Why: I want to use a 8 inch long PCX cylindrical lens with several laser diodes in parallel all shooting into it for higher total beam power. It will make a large rectangle beam output, but I can combine powers of several diodes that way. Will see, maybe it won't behave as I envision, but want to see how it works out.

I have been scratching my head around this subject for a while. When I was a med student I had two weeks of ophthalmology and it was not enough time to pick up optics:cryyy: Good thing I did not go into it or I might have given reading glasses to someone who is nearsighted.

What I am wondering is this. While I can see why one might want to correct the divergence, given the use of multiple converging diodes, does it matter?

 

[RedCowboy]

I have not seen Planters around in a long time, not at this site. I wonder why? His YT Tech Ingredients is posting drone projects. Maybe he got bored ?

 

[diachi]

I have not seen Planters around in a long time, not at this site. I wonder why? His YT Tech Ingredients is posting drone projects. Maybe he got bored ?

He's still got the big dye laser in the background if you take a look at his recent videos. Don't imagine he's completely done!

 

[Radim]

It... might be easier to understand your question if you drew a sketch.

You can collimate only one axis if you like. I'm not sure why you would want to. The other axis will diverge just as it would without collimation. The divergence of the collimated axis depends on the diode's emitting area and final diameter, which depends on the lens.

Exactly. That is the answer I would gave. Well said.

You've not stated which axis. That matters what the answer will be.

Another question on my mind. :crackup:

That confirms my thinking guys, that's all I wanted. Thank you.

E: Why: I want to use a 8 inch long PCX cylindrical lens with several laser diodes in parallel all shooting into it for higher total beam power. It will make a large rectangle beam output, but I can combine powers of several diodes that way. Will see, maybe it won't behave as I envision, but want to see how it works out.

Does it mean it is solved? No further discussion??? :thinking::yabbem::san:

Anyway, your project seems interesting, let us know more... Maybe once you have some results from you experiment, so we can drool a little bit. :beer:

I've been also interested in some cylindrical lens for some time already. Potentialy I think to replace line generators (kind of "multi cylindrical lens") for some laserpainting purposes, where they just do not fit (they have different texture of light scattered in midair).

Anyway it is good to take a ruler, pencil, piece of paper, etc. and draw it. That's what I do when planning composition and thinking about optics and how to use it.

 

[RedCowboy]

The NUBM44 is so divergent that it takes 6X cyl correction of the aggressive axis after a G2 to make about the same size spot/rectangle at 75 feet as a NDB7875 with a 3 element only. Roughly 2 inches long by 1/4 thick or so. Ironically you get about the same at 75 feet with a NUBM44 with a 3 element and 3XBE.

I get a little less than 1/2 inch by a 3/16 with a 44/G2/6Xcyls/3XBE at 75 feet.

I thought if I could get Chinese 2X cyl pairs cheap enough that I could correct, then knife edge in rows and stack the rows such as 5 x 5 or 6 x 6 then into a large beam expander using osram pltb450b diodes, they are selling for around 20 dollars, so you buy a bunch of cheap 12mm modules and Chinese G2 lens and correct, Knife edge, and stack the KE rows then either use a big possibly homemade BE.

That would give you more power in a tighter beam for less money IINM
A 6X6 should be good for 65 watts or so, at least 60, that's if you want a visible beam, otherwise just build a 50w c02.

If you want visible but don't care about burning then for twice the price of 44's you could use NDG7475's that have divergence like the NDB7875, so you could use 4 x NDG 7475's with G2's and cyl correction and knife edge 2 rows of 2 stacked so you have a 2x2 then use a big beam expander for projecting a long distance spot.

Now you said converging so the cheapest would be a steering wheel with a bunch of chunks of 1 inch square aluminum bar with 12mm holes drilled mounted with an angle iron so you can adjust x and y at the 2 attachment points and just use pltb450b diodes with 3 elements all in series with a homemade power supply and adjust for an infinity converging if spotting clouds.

----EDIT---- Rickers has 7875's with the G9 lenses from a zero or very low hour machine and will make you a deal, so you could buy a bunch of those and buy blank lens holders, I bought some for 99 cents each and mounted G9's from rickers 7875's that I made a deal on, then all you need is cyl pairs and either converge or knife edge stack the rows and into a big homemade BE.


https://www.ebay.com/itm/Nichia-NDB...629892&hash=item1a2a1ad0c6:g:Me4AAOSwvihY9oog

https://www.ebay.com/itm/6-35mm-Asp...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

I have not used these yet but I will and they should work for the 7875 with it's own G9
https://www.ebay.com/itm/Anamorphic...m=222693598271&_trksid=p2047675.c100009.m1982


I have not used these with the extra lens, but you could probably use them without it.
https://www.ebay.com/itm/Laser-Beam...m=112374693911&_trksid=p2047675.c100005.m1851


---edit----

You could use 5 or so NUBM44's with G2's + 6X Cyl pairs and knife edge 1 row of 5 and use a really big homemade BE.

 

[steve001]

RCB, really good info, thank you for sharing to that detail, rep when I can.

I found a youtube video you guys might like to see showing four NUBM44 laser diodes knife edged together;



Also, I combined my two videos showing the difference between the beam of this diode when expanded to 2.5 inches wide, and when using a ~6 mm G2 collimation lens.



Video best viewed in full screen HD: https://youtu.be/6-_WhL1PTq4

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Screen captures, left with expanded beam, right no expansion/G2 collimator;

Are the lenses set from each other sum of their focal lengths? I ask because you moved the G lens but did not say if the large lens was moved too.
Technically that steam is a cloud and it's not steam even though everyone calls it steam. ;-)

 

[RedCowboy]

What looks good in the far field and what really does useful work may not look much different to the naked eye, but you can test spot size at a given distance to test your adjustable setup is really doing.

The one on the right is much more capable of igniting wood/paper but from just looking it's impossible to tell, well almost.
Left and center are 44/3E/3XBE and Right is a 44/G2/6Xcyls/3XBE

This looks good but it's clipping 1/3 of the output.

Here's 2 NUBM44 builds, one is using a 44/G7/3XBE and the other ( on the right ) has a 44/G2/6X cyl pair/3XBE ( both drivers are set at 4.5a ) ..........The beams look a lot alike to the naked eye, I don't know that both diodes are positioned the same or not ( rotation wise ), the wood has heat already pumped into it so it flashes up easily, but from a cold start the corrected unit pops out a flame kernel on the wood or paper quickly because the actual spot size is much smaller, but even with the safety glasses the glare is too bright to see it in detail, at least at this distance, but at 75 feet I can zoom to it's tightest and walk out and measure. p.s. Don't make the mistake of measuring MM diode spot size at reduced power, it will be smaller but will enlarge when current is increased.

p.s. This info is more for those interested in condensing power for doing useful work, as for lighting a spot on a distant object or cloud bottom if your greatly improved divergence produces a spot twice as wide and twice as tall as another greatly improved diodes divergence then it will still look good, but the energy is 400% higher in the spot that's half as wide and half as tall, this could make a difference in the ability to see the spot at very long distances, but for the naked eye is becomes a small factor, now observing the far distant spot through binoculars or a scope you can see a difference, anyway the method used depends on what you want to do and how much you want to spend in time and money, for projecting a condensed spot you can get away with a less super concentrated spot, but for doing useful work we have to use more than the naked eye to judge what's going on at a longer distance, again it all depends on what you want to do, we are already going with the most affordable power with MM diodes when something like Alaskans 4W DPSS 532 through a BE should produce much better spots at longer distances, but again the factors of size/cost/ect... all come into play. A TEM00 DPSS beam is much easier to work with, but more expensive and bulky for multi watt applications......and expensive.

I wonder how miniaturized one could make a 4W DPSS 532nm vs, the work of correcting and knife edging 4 x 7475 diodes, both make a fair amount of waste heat and need a bundle of batteries.....Chris do you still have that 4W 532?

---------------------

I built one of these with 650nm 80mw diodes long ago, you can set the bundle diameter and use the final lens to make a tight beam bundle or a wide funnel of beams to a point where they converge, another idea I had but never built is aligning the ring of lasers onto a ring of galvo mirrors.

The reason for sliding lenses is so each laser does not have to articulate for every distance adjustment, and aligning in a cone allows use of a larger ring of lasers and a more manageable size lens.
-----Add a center laser not shown----- 1st lens was concave, final a PCX-----

 

[Radim]

After I said that, I thought it wasn't correct, just moisture in warm air, but isn't that what steam is too?

Edit to answer your edited question: if i adjust the G2 lens much to make the beam wider or smaller inside the tube, I then need to readjust the distance the large PCX lens is from it to collimate the beam better, but only a small amount.

Steam is invisible, people often think of seeing steam, but they see little droplets of water instead.

https://en.m.wikipedia.org/wiki/Steam

Water is overall fascinating.

What looks good in the far field and...

Awesome post. I'll go through it later on more deeply. Thanks. Rep+.

Edit:
After reading your post, thanks again. A lot of information is there. And I agree on theory, now I want to use this in practice as you did. Just with Opto's Beast and likely not combining it with anything, but definitely I would like to do some long distance burning with that and some BE. I'm looking forward to look what optics I could find in my "lab" to get some BE setup to play with. TEM00 greenie portable DPSS of great power and beamspecs, that could be worth to try. Zoomable and focussable BE ideally.

Damn it... :crackup: I've just realized that I have another laserproject to go... So, if the experiments are ok, I will need more lenses to get, or to invest in some awesome BE. Thorlabs should have some. But those, I'm interested in, cost fortune.

Sorry, off topic... But you can see what your post has done to me. :crackup:
But if you feel guilty I'm thinking about drawing my account low for going for something like this, you do not have to. I was thinking about this idea earlier... Long time ago... Now this has been brought to my mind again.

 

[steve001]

Steam is invisible, people often think of seeing steam, but they see little droplets of water instead.

https://en.m.wikipedia.org/wiki/Steam

Water is overall fascinating.



Awesome post. I'll go through it later on more deeply. Thanks. Rep+.

Edit:
After reading your post, thanks again. A lot of information is there. And I agree on theory, now I want to use this in practice as you did. Just with Opto's Beast and likely not combining it with anything, but definitely I would like to do some long distance burning with that and some BE. I'm looking forward to look what optics I could find in my "lab" to get some BE setup to play with. TEM00 greenie portable DPSS of great power and beamspecs, that could be worth to try. Zoomable and focussable BE ideally.

Damn it... :crackup: I've just realized that I have another laserproject to go... So, if the experiments are ok, I will need more lenses to get, or to invest in some awesome BE. Thorlabs should have some. But those, I'm interested in, cost fortune.

Sorry, off topic... But you can see what your post has done to me. :crackup:
But if you feel guilty I'm thinking about drawing my account low for going for something like this, you do not have to. I was thinking about this idea earlier... Long time ago... Now this has been brought to my mind again.

There's one way to see steam. When the air is very humid distant objects will have a blueish tint known as atmospheric perspective.

 

[Andrew124C41]

RCB..Alaskan. I am more interested in creating heat at a distance of from around 15 to 30 feet at most.
I am trying to wrap my head around the wheel with the diodes...exactly how to manipulate each module to obtain convergence. Alaskan....do you want this in something that is portable or handheld?

 

[RedCowboy]

I had thought about a HH rig with 3 corrected NUBM44's each on its own heat sink mount and all on an aluminum plank with the center mounted and the outside 2 articulated, they would have run out adjustments, then you could just turn it on and bring the outside 2 into convergence with the center, you could have a wedge shaped deal so you slide a lever to move the outside 2 inward or outward together. Would be an easy 20+ watts to burn with at 15-30 feet no problem. Still will cost 450 bucks in parts, drivers, batteries, diodes, modules, aluminum, lenses.....make that 550.00 with cyl lenses and G2's and that's doing it yourself.

Would be cheaper to buy the 7875's from Ricker and use the G9 lenses, maybe you could knife edge 8 of them with a surplus KE array, I have dozens I bought from DTR, you would have to stagger your modules in narrow heat sinks or use extra mirrors, but even with just G9 lenses 8 x3w is 24w in a long razorblade line....maybe you could use a prism pair after the KE...???? Do them all together ???? Or if you used a large BE after a KE array of 8 x 7875's with the repurposed G9's, or buy G7's

This is why I keep waiting for a bigger diode, a much bigger diode.