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405nm AR glass lenses - fit AixiZ  FEELER

IgorT

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Custom 405nm (or multilayer) AR coated glass lenses - Interest gauge


At the moment, i am having custom 405nm AR coated single element glass lenses made, mainly for my Blu Rays. They were designed to increase the power of 405nm lasers. The power increase should be 20 - 30%, compared to acrylic lenses. Hopefully more, because of the correct AR coating. Their focal length will be between the acrylics and the Meredith glass lens. The beam will be a bit tighter than with acrylics and more easily focusable, than with the Meredith glass lens.

For comparison, i also ordered a smaller number of the same lenses with a multilayer AR coating (400-750nm), which should be great for red lasers (or any other wavelength), and could allow making focusable ~300mW reds.

The lenses will fit into the plastic AixiZ nut, so they can be used everywhere, where the AixiZ lenses fit.


I will receive the first batch in under three weeks, and post the results (the lenses from the first batch will not be for sale - they are mainly for testing, and they are all spoken for already).

After that, if they test well, we could do a Group Buy and i would order more of them for anyone interested. But because GBs take too long, i decided to post a feeler now, so people can express their interest up front. When the test results are in, you can decide if you want them, and we can have more of them made.


The price i'm paying for the first batch is around 15 Euro ($23.6) a piece. This price is only so you get an approximate idea of what to expect, i won't know the final price until i know, how many we would actually order. Lenses mounted in the lens nut would cost a bit more, because of the extra material involved.

In a GB, they could be a bit cheaper, than what i'm paying now. If you mount it in your own plastic AixiZ lens nut yourself, you only pay for the bare lens, otherwise it's a little extra. But you should be very careful, while doing so! The lenses should not be touched on the active area with your fingers!

The multilayer coated ones cost 1 Euro more. They would work great for reds, but might let a bit less light through with Blue Rays.


If you are interested, post here, with the amount you would like as well as the type of coating, so that i can give the manufacturer an approximate amount, and get a price quote. Interest is non obligatory, this is just so i know the potential number of lenses, that would be ordered if they work as well as they are meant to.




In the next post i will try to explain why these lenses are going to work so well with Blue Rays.
 





IgorT

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Re: 405nm AR coated glass lenses - fit AixiZ  

I'll try to explain why the single element 405nm AR coated glass lenses would increase the power so much, compared to acrylics...


- We know, that plastic blocks a lot of 405nm light (look at the attached graph). Power measurements show, that a clear acrylic lens blocks over 1/3 of 405nm. When there is 80mW after a clear acrylic lens, there is over 120mW behind it!
- AR coatings for the wrong wavelength are also bad for 405nm. A lens both plastic and 650nm AR coated blocks over 2/3 of the light!
- 650nm coated glass lenses are not as bad as 650nm coated acrylics. Even a triple element AixiZ glass lens with 6 650nm coatings will let more light through, than an acrylic lens with two 650nm coatings. But a clear acrylic is still better.
- A single element glass lens with a 650nm AR coating, like the Meredith lens is the best for now.


EDIT: Updated measurements

For example, a PHR-803T diode pushed to >90mW after a clear acrylic lens:
- >120mW before optics (not known exactly yet - this determines how much room for improvement there is theoretically)
- 91mW after a clear acrylic lens (>24.2% decrease, >32% room for improvement)
- 82mW after the triple element glass AixiZ lens with 6 650nm coatings (>31.7% decrease, >46.4% room for improvement)
- 58mW after a 650nm AR coated acrylic lens (>51.7% decrease, >106.9% room for improvement)
- 117mW after a 650nm AR coated Meredith glass lens (30% increase compared to clear acrylics - measured by Jayrob)
(The Meredith info is incorrect. Waiting to receive my own Meredith, and do the measurements myself.)

So both plastic and the wrong coating are a part of the problem, but plastic is the larger part.
A single element glass lens like the Meredith with only two 650nm coatings is the best for now.
But a lens both glass and 405nm AR coated could do miracles.

We also know, that UV light is bad for acrylic lenses. It makes them age very fast, slowly reducing their transmittance and the power of the laser. There are special UV enhanced acrylic lenses, which are used in Blue Ray and HD-DVD optical pickups. They let more 405nm light pass and don't age that fast, but they are useless to us because of their long FL.


The custom lens is designed specifically for Blue Rays, but the multilayer coated one will work for reds as well. It will have a slightly longer FL at 650nm tho.

Custom lens specs:
- 7mm dia
- 2.5mm thickness
- NA 0.615 (without the retaining ring)
- NA 0.46  (with the plastic retaining ring in place)
- EFL 5.435mm (at 405nm - design wavelength, slightly more for 650nm)
- AR coated for 405nm or Multilayer for 400-750nm (reduces reflective losses to under 0.5%)

In comparison, the acrylic lens has a NA of 0.3 and the Meredith has a NA of ~0.4416.

Compared to acrylics, the higher NA allows the Meredith lens to collect more (or all) of the light coming from the diode. The custom lens has an even larger numerical aperture. It will also collect all of the light, even with the retaining ring in place, obstructing 1mm of the edge. I will of course test the power with and without the rim, to see if there is any difference.

The 405nm AR coating will let more light pass than a 650nm coating, as well as reduce reflective losses to under 0.5% and increase the power even further.

The AR coating will also make the higher powers safer for the diode, as there won't be any reflections going back on the die. When a diode is pushed close to the limit, the reflections add up to the total optical power, and if the optical power is at the edge of what the diode can take, the reflections can push it over the edge.. Wrong AR coatings are even worse, when it comes to this, as they increase the reflections due to creating two more surfaces for light to reflect off. Theoretically, the power increase the lens brings, could then be doubled by pushing the diode further, as long as it can take the current - the optical power on the die would stay the same!



I would like to thank Phenol for the incredible amount of research he put into this, DrLava for his advice about the lens specifications and selection and Jayrob and Hemlock_Mike for the info on the Meredith glass lenses.


The attached transmittance graph shows the problem of acrylic materials and UV light, Phenol posted in the PHR diode thread. The uninterrupted line shows the sharp cutoff of regular acrylic lenses at just around 400nm. The other two lines show the behavior of UV enhanced lenses, like the ones found in Blue Ray & HD-DVD optical pickups..

The transmittance starts dropping very fast at shorter wavelengths. This is the largest reason why clear acrylic lenses block so much 405nm light.
 

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IgorT

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Re: 405nm AR coated glass lenses - fit AixiZ  

The list:


- Please post the number of lenses you WOULD want IF they come out the way they are meant to.
- Also specify the type of coating you would like. 405nm for Blue Rays or Multilayer for any laser wavelength (mostly for your reds).


The more lenses we order, the lower the price could be. If you put it into your own plastic AixiZ lens nut by yourself, you can have them at manufacturing cost + shipping. Otherwise, it'll be a few bucks more because of the parts. For the US it would probably be better to send a bunch of them at once to someone reliable from there.


This is just to get an idea of the amount we would order, so that i can get a price quote and tell you how much they will actually cost. After they are tested, you can then decide if you want them or not. If they test well, we can then order the lenses...


Potential orders:

405nm AR coated lenses R<0.2%:
1x TheJunkMonger
2x robjdixon
2x Cyparagon
5x Daguin
2x Scopeguy20
3x Jayrob
2x DarkHorse
1x HappyTomato
1x DanQ
1x Hemlock_Mike
10x Daedal
1x Climbak
1x GooeyGus
1x ndrew2505 (or 2x?)
2x FireMyLaser
2x Abray
2x TheGr8Revealing
1x Midknight
1x Jules
1x lasercrazy
3x LarryQ
3x Dar303
1x Spyderz20x6
1x wicked1 2x?
5x onb00st
1x icecruncher
1x bmansc
1x motorider826
2x OrBy
3x Kenom (4x?)
1x Glaserfan
1x airy52
5x nvmextc
2x Kage (a couple?)
2x docjohn
3x Choar_Sac
1x Brtaman (2x?)
3x Amkdeath (4x?)
2x 110100100
50x heruursciences
4x satseb
1x 360freak (See An Eye?)
5x Sk8ter4241
3x Eagle 1
1x mmykle
1x pwnstar
1x ryo
1x ArRaY
1x thesk8nmidget
1x K-shell
3x tocket
------------------------  180 pieces (or ?!? could the question marks please decide?)




650nm AR coated lenses: Changed to broadband R<1% covered by the mini GB?
1x DarkHorse
1x Hemlock_Mike
1x Climbak
1x Midknight
2x docjohn
1x lasercrazy
2x LikeitBright (or 3x?)
4x satseb
1x Spyderz20x6
1x mmykle
1x pwnstar
1x Artix
--------------------  17 pieces (or 18x?)


Total: 191 pieces
 

IgorT

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Re: 405nm AR coated glass lenses - fit AixiZ  

THE RESULTS ARE IN!


And they are GOOD! ;)


After going through six useless lenses, i found three that work.

The best of them has been selected.


Here are the results:
- 4x Blu Ray:     ~23% increase :)
- 6x Blu Ray:     24.2% increase   :D
- High WL. PHR: 26% increase      ;D
- Low WL. PHR:  43.2% increase   :eek:


I have not measured an increase of less than 23% yet!  :cool:
The diode would need to have a very long wavelength to get increased less than 23%. Or an extremelly good aspect ratio, like reds..



Still to be tested:
- Another "fresh" short WL. PHR (for confirmation of the high percentage)
- more 4x Blu Ray diodes (GBW sled)
- Red diodes (16x & open can)
- AND OF COURSE 12x diodes!!! :eek:


The exact increase depends on:
- actual wavelength of the particular diode
- beam distribution profile of the diode


Because of this, the exact increase will vary more among diodes that vary more in wavelength (PHRs), and be more consistent in with more consistent diodes (4x's & 6x's).
The increase also varies between different diode types, due to their different beam profiles.

There is no variation between diodes on the glass lens - it brings out all there is with each of them!

The reason the increase varies is because "increase" is based on comparison with AixiZ acrylics, and those waste different percentages of power depending on the wavelength (shorter wl's pass acrylics harder), and the beam distribution (with flatter beam more gets lost in acrylics, due to more power being in the slow axis which is clipped by the low NA of acrylics).

Diodes with rounder beams pass acrylics a little bit easier, because they have more power in the slow axis, which does not get clipped by the low NA of the acrylic lens. Because of that, a PHR of the same wavelength as a 6x will get increased in power more, as the acrylic lens wasted more of the PHR's power.
 
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Re: 405nm AR coated glass lenses - fit AixiZ &nbsp

IgorT said:
Custom 405nm (or wide band) AR coated glass lenses


At the moment, i am having custom 405nm AR coated single element glass lenses made, mainly for Blu Rays. They were designed to increase the power of 405nm lasers. The power increase should be around 40%, but it could be close to 50% compared to acrylic lenses! Their focal length will be between the acrylics and the Meredith glass lens. The beam will be a bit tighter than with acrylics and more focusable, than with the Meredith glass lens.

For comparison, i also ordered a smaller number of the same lenses with a multilayer AR coating (400-750nm), which should be great for red lasers (or any other wavelength), and could allow making focusable ~300mW reds.

The lenses will fit into the plastic AixiZ nut, so they can be used everywhere, where the AixiZ lenses fit.


I will receive the first batch in under three weeks, and post the results. After that, we could do a Group Buy. But because GBs take too long, i decided to post a feeler now, so people can express their interest up front, and when the results are in, you can decide if you want them.

The price for the first batch will be around 15 Euro ($23.6 at the moment) a piece, but in a GB, they could be a bit cheaper. If you mount it into the plastic lens nut yourself, the price would be even lower.
The multilayer coated ones cost 1 Euro more. They would work great for reds, but might let a bit less light through with Blue Rays.


If you are interested, post here, with the amount you would like as well as the type of coating, so that i can give the manufacturer an approximate amount, and get a price quote. Interest is non obligatory, this is just so i know the potential number of lenses, that would be ordered if they work as well as they are meant to.




In the next post i will try to explain why these lenses are going to work so well with Blue Rays.


Igort - not calling you out, or your reputation at all - but I AM calling out your data. There simply is no way possible for a 405nm coated optic to increase any normal diode's output by a factor of that much (40-50% ??). If you test the raw, unimpeded output of any 405nm diode, and then test that same diode's output with one of your lenses, it should come out ALMOST equal - and if you tested the RAW output vs an Aixiz Acrylic or Glass Lens, I am sure you will not find that the lens is blocking 40%-50% of the output power either.

I believe you have been given some misleading, and impossible data figures - there simply is no way that 40-50% of the 405nm diodes' output is being blocked by non-coated optics. I think you need to go back to the drawing board a little bit on this idea unfortunately - and possibly ask for proof from whatever entity gave you that impossible data. This ain't rocket science, but it damned sure is LASER science - and no lens, AR coated or not AR coated is going to block 40%-50% of a lasers' output.
 

IgorT

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Re: 405nm AR coated glass lenses - fit AixiZ &nbsp

Greg, i fully understand your concern, and the data should be questioned, tested and verified. I questioned it for a very long time myself, with the help of others.

Besides, i am not not promising anything just yet. The only reason i started this before the final testing, is because GBs take very long, and this way, if it works out, others could get them a bit sooner. I am already getting mine.


I am paying for the first batch out of my own pocket, and only if they work as well as they are supposed to, could we do a GB. This is just to see how many people WOULD be interested, IF the lenses work.

I realize, that i am taking a risk here, but for the first batch, it is my own money and my own risk. And i wouldn't be doing it, if i didn't have enough information. And it would not cross my mind to do a GB, if they didn't work as promised. If they should fail for some reason, i will say so, and not start a GB.


What i do know for sure at this moment, is that a Meredith lens brings an increase of 46% (EDIT: 30% actually, i was wrong), compared to a Blu Ray with an acrylic lens at the same current. So 30% or more is still a reasonable expectation, just because of the correct coating. And i have done the no optics / acrylic optics / 650nm AR coated acrylic optics measurements myself.



Oh, and the "up to 40%" is the (theoretical) increase FROM the acrylic lens, not a decrease WITH an acrylic lens. The percentage depends on the direction in which you're doing the calculation.
A 33% decrease in power (with acrylics) would mean you have room for 50% of improvement (minus the losses in glass and the coating of course).

For example: 120mW no optics -> 80mW with acrylics would be a 33.3% decrease.
80mW acrylics -> 120mW no optics would be 50% more..
80mW acrylics -> 104mW Meredith is a 30% increase.
120mW no optics -> 40mW 650nm AR acrylics would be a 66.6% decrease!


This is why i said that acrylics block ~1/3 of the light, and that the custom lens could bring almost 40% increase in comparison. The Meredith already brings 30% on top of an acrylic even with a 650nm coating. The custom lens will have 405nm coating and a larger numerical aperture.



But of course, a lot of this is just calculations. I will post the actual results as well as send some out for testing, BEFORE starting anything here. Again, i just want to know how many people would be interested if it works out, like it's supposed to, so that i can ask for the final price.


I am aware, that the numbers sound incredible, but so does the 46% (EDIT: 30% actualy - i was wrong) increase with the Meredith lens. When i first heard it, i couldn't believe it myself, especially, since i did not know, there was so much power behind the lens.

If you want a lens for your own testing and verification, just let me know, and i'll send you one after i get them.



EDIT: The Meredith makes an increase of 30% (not 46% - i had the wrong info) even tho it has a 650nm coating.. Updated the numbers.
You were right, this part of the calculation was a bit too optimistic. But 30% is the least we can expect, and since the lens is designed for 405nm, it could be a bit more, depending on the actual raw output of the diode.
 
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Re: 405nm AR coated glass lenses - fit AixiZ  FEE

i am in for 2 :D

BTW do the aixiz acrylic lenses have ar coating? Because if i can get a range of lenses, i can use it in defferent places - ie i won't take a 115mw laser around with me a lot, but a ~45mw laser would be better
 

IgorT

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Re: 405nm AR coated glass lenses - fit AixiZ &nbsp

The AixiZ acrylic lenses are usually clear. The ones i received from AixiZ directly were all clear and the ones i received from DX were also clear. They are the best cheap Blu Ray solution for now. The Meredith lens costs more, but brings the most power at the moment. The custom lens should work as well as the Meredith, but it will cost less, because it fits into AixiZ modules or anywhere an AixiZ lens fits.


If you want to check for coating, you can look at the lens under a certain light, and you would see a blueish coating, if it has a 650nm AR coating. I tested an 80mW Blu Ray with the 650nm AR coated Dilda lens, and got just over 40mW. This can somewhat vary between types of coatings of course.



Please also post the type of coating you would want if the lens turns out well: 405nm OR Multilayer (for all laser wavelengths)...
The coatings are done at the end of the manufacturing process, so we can order whatever combination we want.


Again, this is just to get an idea of the number ordered, and to get the final price quote. All i know for now, is that they will cost around 15 Euro (just the lens). If enough are ordered, they could cost a bit less by themselves or a few dollars more, mounted in the lens nut.
 

IgorT

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Ok, i may be a bit slow to respond for a while, because i have a huge workload at the moment. But people suggested i should start the feeler now, so it doesn't take too long after the lenses are tested.

I will try to answer all questions and update the list as fast as i can.
 

daguin

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At least 5 (more pending timing and availability of funds) coated for 405nm

Peace,
dave
 

jayrob

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Re: 405nm AR coated glass lenses - fit AixiZ *

IgorT said:
80mW acrylics -> 117mW Meredith is a 46% increase.

If you got that data from my 117mW build, I just want to clarify that my measurements were from 90mW's Meredith acrylic to 117mW's (Meredith glass) - a 30% increase.

But this increase using the Meredith glass lens, is mostly due to the position of the lens. (very close to the LD)

That said, I am very interested in your research here Igor! If your results are positive. I would like at least 3 lenses. :)

Thanks for your work!
Jay
 
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IgorT

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I thought it was 90mA. Thanks for the correction, i will update the info. If you could set a diode to 80mW with acrylics and measure with the Meredith, that would help a lot.


Otherwise, i know about the position of the Meredith lens. But what matters to the amount of light collection is the NA (numerical aperture) of the lens, which is a factor of the focal length (and with it the distance from the diode) and the effective diameter. The Meredith NA is 0.4416 and the custom lens NA is 0.46 with the retaining rim and 0.615 without it. As long as the NA is large enough, all of the light will be collected. With the custom lens there is even a certain safety margin on top.


P.S. You're getting one from the first batch already.
 
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Re: 405nm AR glass lenses - fit AixiZ  FEELER

I believe I would take 2 Ar for 405 nm.  I will want more, so I'll let you know if I find the funds.  For sure, I want my IgorT lasers to output a noticeably higher output power, they are miniature beasts as it is!
Anyway, my bet is, the best gain is when these are in the units w/ higher outputs to begin with!  So, of course the IgorT lasers s/b great with these!
 

IgorT

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25 -> 39 would be a 50% increase. For this, the lens would have to block almost no light, as there is only 50% more behind an acrylic lens.

30% is a safe bet, close to 40% might still be possible. But we won't know for sure, until i test them. Again: This is just so we know how many people WOULD be interested IF the lenses work.

I can not promise anything just yet. But as long as it collects all the light, it should be a great lens for 405nm, simply because of the coating. And the NA of the lens is higher than the NA of the diode, so there is no reason it wouldn't collect all the light.


The power increase will be in percentage, regardless of power. Of course it will make much more sense to use them with high powered Blu(e) Rays.
 




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