405nm AR glass lenses - fit AixiZ FEELER

[jed2i]

Re: 405nm AR glass lenses - fit AixiZ  FEELER

forget my order... i'm little short on cash

 

[Zom-B]

I'm also interested in one 405 and one broadband lens. That is, if the price drops to a reasonable amount.

I have my own lens nuts, so are the lenses already made to fit them? I read somewhere that they'll be 7mm, but I don't know if this is old information.

 

[IgorT]

Re: 405nm AR glass lenses - fit AixiZ  FEELER

Wow, there was a lot of action here, while i was gone.... I had a family emergency i had to take care of, so i was barelly ever at the computer during the week.


However, since several people offered to help me out finantially and buy a spherical custom lens (v1), i decided to take this one step further. I paid to have COATED samples made and shipped to me! There is a quality assurance thing they need to take care of, and these two will show how well they do this.

Not to mention that these will give the answer the uncoated ones can't! The powah!

And since some other manufacturers suddenly replied, i told them if they can get the samples to me in time and if they are better in any way, we might choose those..

So stay tuned, this is suddenly becoming very interesting!


Otherwise there is one thing we need to discuss. Everyone would seem to want THIN beams, as in ridiculously thin. I have a ridiculously thin beam on a red, yes. In the meanwhile i actually made a red with a beam THINNER than a green!

But do we REALLY want to go THAT far? To be honest, i would prefer the beam to be medium thin, so that it is still good at focusing into a tiny spot at distances, and so that we don't end up with a ridiculous divergence on top.

Not to mention that the short FL required for the ridiculously thin beam reqires the lens to be so deep, that the latest DX modules can not even support it, and even with the actual AixiZ modules we would need custom adapters, if we wanted to be able to use focusing rings on the lens nuts. I can have the adaptors made, sure, but $$$$.....


Until now there was one option - the third. And i thought it was the last. Suddenly i am showered in options, so we actually get to choose. But unfortunatelly we only get to choose once! The second time would only be possible with another BIG order, which is not likelly to happen soon. So we have to choose wiselly!


Sure, i want a thinner beam too. And i can also get a ridiculously thin beam. But i want a good universal lens, the best of both worlds. Not just a temporary attraction, which you get tired of soon.


I will make the pictures. Horribly busy ATM. I spent every spare minute on this, but details i'll post over the weekend. All the lenses are on the way to me with express mail, so i can do the final testing shortly, and on coated lenses, which i thought impossible until now.

 

[artix]

Re: 405nm AR glass lenses - fit AixiZ  FEELER

Awesome!

I would want a beam that is about ~2-3mm

 

[Lasercrazy]

Re: 405nm AR glass lenses - fit AixiZ  FEELER

I'd like the lens to have a small dot at decent distance. I 1mm beam that quicly turns into a huge spotlight is useless.

 

[dar303]

Re: 405nm AR glass lenses - fit AixiZ  FEELER

I'm going to use these lenses for laser show use so as long as it fits the scanner mirrors (4mm or so) its fine. 2-3mm is good. A multicoated lens that can be used for reds would be nice since the green and blue beams is pretty thin but the reds are fat and usually a lot is lost on the mirrors.

 

[Zom-B]

red has a worse divergence than green. If for example the green beam is 1.5mm and divergence is 0.5mRad (near theoretical bound), the divergence with a red could be 1mRad or worse (does anyone recall the exact formula? pullbangdead?)

 

[IgorT]

Re: 405nm AR glass lenses - fit AixiZ  FEELER

I'd like the lens to have a small dot at decent distance. I 1mm beam that quicly turns into a huge spotlight is useless.

Exactly.. That red i made with a ridiculously thin beam (<1mm) has a huge spot on a wall just 4m away... I can make a smaller spot with the regular acrylics at a much greater distance... The thin beam is fun to see, but it's only thin from close up, and focusing doesn't work at all.

That's why most of the lenses i had made or bought so far, have FLs from 5.7-6.3mm (in comparison, AixiZ acrylics is 7.3 or so - for 650nm, less for blu). A 4.3mm FL makes a ridiculously thin beam on the other hand. It's fun to see it, but it's not that usefull. And it doesn't even look that much brighter. However such a lens is on the way as well and coated.

A ~3mm beam on the other hand is nice and tight, but still very much focusable, and the divergence is MUCH lower. The beam thickness will of course differ between a red and a blu, since the same lens will be used.


It is similar with greens. Green pens are made to have thin beams that you can use for burning, but at a distance, the spot becomes huge. My 500mW green has a thicker beam than any other green i have seen so far (i asked for low divergence), but because of that the spot is small on a building a kilometer away or more.

So something like that would be ideal in my oppinion, and we are getting something like that.


There is one benefit with the very short FLs - high numerical apperture at a similar effective diameter of the lens. A short FL will have an easier job at collecting all of the light. But that power is then rendered useless when you can't burn, nor point around at night so well, because the beam gets so fat at a distance, that the energy density drops bellow that of the same laser with a regular acrylics.. Pointed at the sky, a beam that starts fat but diverges less will seem to extend further than one that starts thin but has a huge divergence.


Anyway, i'm very excited about getting the coated samples! They cost me quite a bit, but they will give the FINAL answers we are all waiting for. After those are tested, there will be no more question marks. We can just make the big order all at once without any risk.

 

[thesk8nmidget]

Re: 405nm AR glass lenses - fit AixiZ  FEELER

;D
im very excited! now i just need to get some 405nm pbs cubes made and i will have 400mws of 405 in my scanner

 

[Jimmymcjimthejim]

Re: 405nm AR glass lenses - fit AixiZ  FEELER

I think that 2-3mm beams are good enough, as long as I can get good divergence, and still focus it for burning, that would be great!
Oh, and I don't mind about the focusing rings. The lens nut would be fine how it is.

 

[Teo128]

Re: 405nm AR glass lenses - fit AixiZ  FEELER

I'll be intersted in a 405nm coated one in a aixiz plastic nut

 

[scopeguy20]

Re: 405nm AR glass lenses - fit AixiZ  FEELER

  I for one, have been following the quest for the best lens for some time now.  I firmly believe that the work has been long and has cost a good bit of time and money that Igor has not been complaining about.  We are going to have a far better choice than was possible before, and the lens will give better beam qualities as well as a better transmission % .
  In very high output diodes the chances of losing a diode to catastrophic optical damage, (COD), will be lower, and these lenses being glass with a more durable surface could be cleaned, (with care), and won't degrade from age and light damage like the acrylics surely would.
 If by now you are wondering why I'm going on about this, I fear that it's too easy to think that these are not so much better than the older choices, and I also think that, some folks would not see all the giving Igor is doing on his quest for our benefits.  I would hope that most folks though, realize that if your high mW diode survives, you have saved the cost of burning up another diode, if your lens c/b cleaned you  have saved the cost of another lens,  etc.  and Igor has been engineering, testing, developing, costing, procuring, assembling, etc. etc. and all at no investment or cost to us.  I hope we all remember to rep, Igor and find the great value in these lenses so engineered near perfection.  

 

[daguin]

Re: 405nm AR glass lenses - fit AixiZ  FEELER

Members who have not been privy to this process have no idea how much money and effort IgorT has expended in his quest for a better lens for us. I wouldn't presume to tell everyone how much money IgorT has already spent of his own money on this, but suffice it to say that he has spent more money just researching these things than most of you have spent on lasers in your entire life!

Help cover his cots. Buy a laser from him.

Peace,
dave

 

[Racer96heat]

Help cover his cots. Buy a laser from him.

Oh no! The costs were so much that IgorT is now living in a cot

scopeguy and daguin are right. The amount of work that IgorT has been putting into this has been amazing. I've been trying to catch up on all of the information by reading through various IgorT threads, as well as email with him, and he (as well as daguin) are just great people. If I could rep people, I'd do it. I want to thank both of them for their help.

Mike

 

[Zom-B]

Just to give an indication of how much power a laser diode can emit, here's my story of today.

I was experimenting with several different lenses, in an attempt to pre-collimate the beam a little, before final collimation is done by the standard aixiz lens. For this, I tried putting several lenses directly on the laser diode. I attempted to capture the wide angle of radiance, of which lots gets normally lost because it shines on the inside of the aixiz. I made a simple diagram:

Then I stumbled upon one lens (i think it was the objective lens of the PHR sled itself, because I have lots of them) which is is so strong, that even when it is sitting directly on top of the laser diode can, it still collimates the beam. Of course this is useless, but I could clearly see the beam converge to a small waist, about 2 inches above the device, and then diverging again. Later, when I put back my normal aixiz lens (without supplementary lenses!) and I focused it to about the same distance, I was like, where's the beam? Oh I can see it if I hold it this and that way. To be sure, I removed the aixiz lens and placed the super strong objective lens on top again, and after turning on the laser, I suddenly saw a very bright beam again!.

[Edit] It is not a PHR lens, so it must be a Sony DRU-190A lens. The power with the objective lens is about 190mW compared to 130mW with the aixiz lens. Obviously, the power also drops considerably when focusing the beam to a dot with an aixiz nut because you screw it further out. This laser is normally 150mW when focused at inf. (the batteries of my meter are empty, so the readings are not very accurate, though another calibrated laser hits the spot right on within one mW)

 

[IgorT]

Re: 405nm AR glass lenses - fit AixiZ  FEELER

Wait what?!?! You measured a jump from 130 to 190mW switching AixiZ to this other lens?

AixiZ lenses do have a low NA of only 0.3, that's why they clip the fast axis of the output, and make the spot round in comparison to what the output really looks like. That and the bad material means big losses, but i was estimating like 25% max.. You're saying 46%?!?

Low wavelength PHRs pass AixiZ a little harder than high wavelength ones, but that translates to only a few percent increase more, after you put in AR coated glass.

EDIT: Oh, you said the acrylic was focused at two inches. But 150 to 190 is still a 26.7% difference. But it is closer to my estimations.


Well, we will soon know for sure!

Last week i paid for two finalised (coated) lenses to be delivered to me with express. They should be here soon.

The two lenses are:
#1 - FL 6.3mm, NA 0.4, dia 7mm, AR 400-700nm
#2 - FL 4.56mm, NA 0.55, dia 6.33mm, AR 400-700nm

While talking to the manufacturer on the phone, the guy asked me what "our application" is (they probably think we are developing a system to keep sattelites in orbit via laser positioning), to help me select the best lens. I said i want to get out the maximum power possible, in a straight beam with no distortions around.

There was this third lens i wanted to order, but didn't cos it was not within our budget. But after we talked, the guy said he will throw this lens in for free, and that if it works for us, we can have it at the cost of the first two. He obviously knew why i didn't order it.

The third lens is:
#3 - FL 4.02mm, NA 0.6, dia 6.33mm, AR 380-445nm



The first lens i ordered, because i want at least one medium FL lens for myself (for a medium thick beam), and because this one would work in an AixiZ module directly. But the NA being only 0.4 it might not capture all of the diode output.


The second lens i selected for it's properties. It seemed like the perfect lens for capturing as much output as possible, and creating a nice thin beam. After doing some research, i realized, that this is the "same" lens used in the Meredith modules, but with an enlarged diameter, and a coating suitable for blu rays! This should indeed be a very good lens! I did a 405nm reflection measurement off the Meredith a while ago, and i measured 6%. It wasn't a perfect measurement, but it can't be much more, and 6-7% is like uncoated lenses. That means, that to a blu ray, the NIR coating of a Meredith looks like no coating - unlike some 650nm coatings, it doesn't make thigs worse. Another thing this means is, that if the Meredith had a 405nm suitable coating, the power would be 5-6% higher. And that is what we are getting! A blu "meredith" lens! This lens has a sister lens with 6mm dia, that is a direct replacement for the Kodak A390 lens found in Meredith modules. With the 6.3mm, the only difference is the diameter, but this larger diameter also gives it the ability to capture a wider ouptut!


I was told that the third lens was the most suitable lens for 405nm diodes. Before that, i was looking at another manufacturer (the one that makes ThorLab's lenses), that had a special lens they developed specifically for Nichia diodes. I wanted to buy it, but one cost 68€, and for <500, the price was 38€ a piece! They said we could talk about the price once it comes to larger numbers... They don't understand, that 250 is a larger number for us...  :


But while researching what i ordered, i realized that the third lens, the one the manufacturer threw in for free, is THE SAME lens - just made by another manufacturer. All the properties are identical, and they are direct substitutes for each other.


This lens is considered the best blue lens in the world! If there is any power left, that lens #2 can't bring out, this one will! This lens was designed to Nichia's specifications for a blu diode, and has the design centered at 408nm, with the coating shifted down, to cover blu even better than the broadband! The NA is so high, that it should collect all there is.

If there really is >26.7% more light behind an AixiZ acrylics, this is the lens, that would bring it out! That's what it was made for!


So stay tuned.. The end is near....


P.S. About making a separate GB thread. Yeah, that might be a good idea, after i have the final results in. This thread could be considered as the project thread....