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FS: >110mW PHR, >140mW 4x & >170mW 6x Blu-Rays

jayrob

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Igor's medium lens will have less splash, with just a little less power increase...

FrancoRob, very good summery. And a great job with your testing! :gj:
Jay
 





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Is this whole debate sill about "splash"? I thought all this was already settled? Or am I wrong?

Yes, TJ, you're right, it was already settled! I just have had the opportunity to take some shots of the IgorT FIRST (and unique, actually) Medium Lens beam, making a comparison....:yh:
 

IgorT

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Ok, i only now got back... The moving took half of last week and after that i decided to take a few days off. Probably the only "vacation" i'll get this year.


Now on for some more work.. :)


Luckily the 8x test diode from Kendall arrived while i was away, and i'm getting ready to test it today! :drool:




P.S. I hope i didn't miss anything too much while i was gone. Need to check all emails and PM's, if anyone is waiting for a reply you'll get it today..
 
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IgorT

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Just so you know, LarryDFW is using the exact same optic as my 405-G-1. I'm sure your test results will be the exact same as with mine...
Jay

Hey guys!

You seem to have done quite a bit of playing around while i was away... :)


Jay: You are completelly correct, i don't see any reason for the same lens mounted slightly differently to produce different results from your assembly.

Even my short FL custom lens would give nearly identical results to both (with minimal differences in beam diameter, due to FL).


Also, you are correct in another thing you said. For a proper comparison, the lens has to be compared on the SAME DIODE.

When i get the lenses back from you mounted, i will test each on every different diode type i have, one with a long and one with a short wavelength, to determine the ranges of increase to expect for each lens/diode combo we have so far....



Unfortunatelly i had to ask Franco not to remove the lens due to the way it is mounted at the moment. I have to take utmost care for the spring not to touch the glass and scratch the coating, when mounting the medium lens, something that will not be a problem, once it's properly mounted anymore. But since it's the only one i've got at the moment, i had to ask Franco not to take it out, just in case....



Franco: Thanks for all the tests. You know what would be the most interesting? As Jay said, no one uses the lens unfocused, but we also need to enlarge the output to see what it does...

For that i use a lens out of the Wicked Lasers lens-kit, to enlarge the output of two lasers focussed to infinity...



As for the patterns the lenses produce within and outside the dot (in referrence to Traveller's concerns), i'll make sure i take very detailed photos once my lens is properly mounted by Jay.

At the moment it's in an improvised imperfect mount, which causes some distortions around the edge of the beam.

I'm also making some drawings, which will explain nicelly, what the various lenses do to the beam and the splatter, and why.



Traveller: I said you'd be the next to test the lens, but since i want to speed up the process, i'd like to have it properly mounted by Jay first, so i can do the final tests (actual power increase - currently reduced by the imperfect mounting, and other tests), and then i'll send it to you for a second review, ok?

I'm especially interested in your review, since you can see the splash even with an AixiZ lens, something which most people can't, due to the 405nm glare...


In reality, every single lens has that "splash", regardless of FL or NA. But it's the FL that determines how big it will be (shorter FL = larger side projection), and if the FL is short enough, the splash becomes larger and comes out of the hiding within the 405nm glare.....


Anyway, the drawings will explain it all nicelly. I'll also incorporate your photos of the splash into them, since you took the best photos of that, since you see it best and know what to set the focus on... :yh:


And i'd also ask you to email me some of your splash photos, so i can select the most suitable one for incorporation into the drawings.... I'd appreciate that very much!
 
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IgorT

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Re: FS: >120mW PHR, 170-210mW 6x & NEW 8x Blu-Rays!!

Yea, I know, Igor said this 6x output is 265mW, but I have noticed that after the "dressing" upgrade, Jerry has set my LaserBee I De Luxe to be a little "stingy" in the readings...:yh:

I think i said in an email to expect 260-265mW depending on ambient temperature.. If i didn't, then i should have.. :angel:

265mW is the most i got on my meter, when the temperature was between 20-24°C... Later on, as temperatures got higher, i obviously got less, since diodes drop in efficiency a bit with temperature....



If i were to send this laser to Electron, and he would do the measurement at the same temperature as me, he would get the same number, as we discovered with the last laser i made for him (i declared it as 208mW now look at his graph)... ;)



With the first laser i made for him, we came to the conclusion, that his meter shows 1.96% less than mine, so i thought mine was +/-3%.... But we must have done something wrong back then, because once we repeated the experiment at a higher power (= better accuracy) and at equalised temperatures, we got the same numbers! :yh:

A short calculation later, i found that my meter is either spot on with his, or 0.5% away at most, giving it an accuracy of 1-1.5%... :evil:


I was very lucky with the thermopile i got from that surpluss stock! :angel:




P.S. Franco: How is that experimental diode killer ~320mW red i sent you? Still alive and well, or have you managed to kill it yet?
 
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IgorT

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Oh, and Franco.....

You have to do some burning tests with the medium lens, while you still have it!

I think you'll find it focuses beautifully! :yh:
 

ixfd64

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You might want to update the links on your first post (some links no longer work after the vBulletin conversion).

Also, do you have plans to sell higher-powered models in the future? I think some Blu-ray lasers can go up to over 400 mW now.
 

IgorT

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ixfd64: Yes, a LOT of posts are in complete chaos now. I thought i fixed most of my first page, but i better check again... Thanks for the reminder...



As for higher power models. I will ALWAYS be making the higher power lasers possible with the best diodes available at the moment.


Some diodes can go over 400mW yes. But not safelly. I am very sorry, but i will NOT pretend that it is safe to power an 8x to >400mW just to spare people's feelings, like i did with PHRs and >140mW....


The 8x diodes might be capable of safelly* (definition below) going CLOSE TO 400mW with AR coated glass lenses. I am making one such laser for FrancoG right now actually.

But you have to keep in mind, that his build required me to order a $200 drive from the US, pay double shipping on it, and have a friend from the US remove the sled from it first. Only then does my work start!


The 6x lasers i make require a $55 diode. But not just any $55 diode! I weed out 15% of the weakest ones, and sort the rest by efficiency and wavelength, which i determine during the pre-testing.

Since around 15% are completelly useless and the rest vary A LOT, the cost of the good ones is actually higher and varies based on efficiency and wavelength.


But even tho i am the only one who even does such extensive (or even any) diode pre-testing and only use the good ones, some people think that my prices are too high!


Now imagine what a laser made with a $250 diode would cost! Especially if some of them were weaker! And what would happen if one would then die?!? A few diodes always die, regardless of how careful and reasonable with powers you are....



I am constantly looking for higher power diodes, and when i find them, i will offer higher power lasers, their powers will be based on extensive testing, and you'll know when i will offer them....


I thought i'd get 8x diodes now, but i just heard of mixed results. I have a test sample here, and will test it tonight and then cycle it to death and post the results. But it might not live up to expectations..


However i also have another source of potentially higher power diodes, in this case for the second time ever with known ratings, and will test it soon too. If that one turns out to be as good as 8x's, i will soon be offering <400mW BluRays... Especially once my medium custom lens is ready...



* "safelly" (definition):
- a power where most diodes can last long enough in a pointer to provide the user with a year (or several) of normal use or in some cases even outlive the user's interest.
- a minimum of 100-150h or more = a year or years of intense use as a pointer.

NOTE: Keep in mind, diodes are meant to live for 1000h+, but in this hobby, we trade some of that life for more power. However there are certain limits i don't want cross.

For example, i don't want to make ~15h lasers and then indoctrinate my buyers to be afraid of an imaginary Duty Cycle Monster, so they would spread these 15 hours over many months by artificially limiting their own laser use. That's why i often keep my power recommendations lower than most....

EXCEPTIONS: If you ask me for a bizzare power and are aware of the consequences you can of course get it. But you have to be aware that it's an experiment...
 

IgorT

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8x UPDATE


While i was away i received several 8x diode reservations, but also found, that the 8x diodes may not be living up to expectations..

I still have to test my sample, but i'm not too optimistic..



HOWEVER this does NOT mean that there is no higher power diode in the near future!

In fact i already ordered another diode that will very likelly be just as good as an 8x, and will test it in just over a week!


So i'm still taking reservations for the higher power lasers.


As before the reservations are only valid if the diodes manage to supply such powers. Otherwise they can be canceled at any time, or changed to 6x orders....
 
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Traveller: ... i'd like to have it properly mounted by Jay first ... and then i'll send it to you for a second review, ok? ... i'd also ask you to email me some of your splash photos

Hey hombre,

that sounds great, but I'd just assume be one of your first customers while we're at it :D - Franco's testing was quite intense and he's got me sold, Jay sold, Ken sold and I'm sure a whole bunch of others too ;)

So if you're planning on ordering a small first batch, I'm ready to buy a JayRob-mounted IgorT medium lens at "standard" cost (i.e. I don't want to wait on any GBs ...anymore... :whistle:)

As for pics, I have ALL my splash pics along with all my Laser-topic pics over at my Flickr site. You can download any size you wish, from small up to original size. All pics are documented so you know what you'Re looking at.
 

IgorT

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Hey hombre,

that sounds great, but I'd just assume be one of your first customers while we're at it :D - Franco's testing was quite intense and he's got me sold, Jay sold, Ken sold and I'm sure a whole bunch of others too ;)

So if you're planning on ordering a small first batch, I'm ready to buy a JayRob-mounted IgorT medium lens at "standard" cost (i.e. I don't want to wait on any GBs ...anymore... :whistle:)

That's exactly what we're doing here... A Test-Buy at "standard cost"..

It will me much easier now, since now people at least respect the cost of precision molded aspherics!


You should see at the very start of the lens project how people were complaining, when i still thought it could be done for $20-25!
I became too obsessed trying to make it as cheap as possible, and only lost money in the process.. :undecided:

If it wasn't for the people complaining about $25, i would have done a test buy long ago! :yabbem:


But now, Franco only has a few more tests to do (i allowed him to remove the lens, if he does not replace the spring upon reinsertion of the lens), and then he just has to ship it back and it's off to Jay.


I was hoping Jay could do all the mounts, but it seems the medium lens costs more in small quantities. So to get to "standard price" i will have to have my lens nuts CNC made.

Jay will provide the dimensions with his expertise. And hopefully also mount my other two lenses from the same manufacturer, so i can finally put them to proper use...


But after i do the final tests, and start the lens nut production, i can still send the proto medium lens for a final review to you... There will be enough time during order collecting.



As for pics, I have ALL my splash pics along with all my Laser-topic pics over at my Flickr site. You can download any size you wish, from small up to original size. All pics are documented so you know what you'Re looking at.

Right, i forgot about that.

I will go through them and pick the one i liked the most... Then just resize it for different FLs and paste into my drawings.

Thanks!
 
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IgorT

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THERE HAS BEEN SOME CONFUSION ABOUT THE LENSES

ANYONE WHO WANTS TO UNDERSTAND WHAT IS GOING ON, PLEASE READ THIS:



Now, let us come back to the meaning of the pictures: as you surely remember, Igor made a long research about the lenses that were best suitable for BR; he found three lenses: v1, v2 and v3.

He concluded that the v2 (Medium Lens) was the best compromise between power and beam shape:

So, to get a better beam shape, his lens loose a 2% of P.O. respect your. And this is clear to everybody that have followed all the lens history. Your lens has an increase of 28%. So it burns more, whatever the diode beam shape/splash is.

Shit, guys, i don't know how i overlooked this yesterday, maybe it had to do with the fact that i spent the whole day just answering emails...


There is a MASSIVE MISUNDERSTANDING going on here!


This is NOT the v2 lens i was talking about there! It's another lens entirelly! And it's actual final power increase is not even known yet, due to imperfect mounting!

From the limited tests i was able to do (limited due to imperfect mounting), the lens currently being tested by FrancoG has to waste approx 7-8% compared to my short FL lens or Jay's lens, in order to achieve a circular beam shape and low splash!


My v2 lens is nearly identical to Jay's lens in all specs. It's possible it has 2% less in power however to establish that for sure, they would have to be compared on the SAME DIODE, after PROPER MOUNTING!

But the v2 lens gives the same shape of beam as well as the same side projections!


The v3 lens was the so called "Nichia Lens", or rather what my manufacturer calls a "low performance version" of the "Nichia Lens" - which basically means they were refractometer rejects - lenses that were shown not to be good enough to read or write a BR disk, but the manufacturer was hoping, they could still be good enough for our neeeds.


Since the v3 showed more side projections, i decided the v2 is better at that time. Also since the v2 had a broadband coating and could be used with reds, while the v3 had a 408nm centered coating as per Nichia specs...



But after all was said and done, the lens i put into my personal laser was the v1!


Why? Because i liked the beam and spot better, and because while it had a lower power, it burned a hell of a lot better, due to more beam volume.



The v1 is what FrancoG is currently testing!
The lens that gave around ~18% of increase on extremelly high wavelength diodes! NOT the v2 that did 26%! (on average diodes the increase of both is higher of course)

Hmm, i only now realized this, after seeing Franco dig up my old test results, but at that time i obviously found ~8% of difference between the v1 and v2. And during my latest tests i found 7.5-8% of difference between the v1 and Jay's lens. I have not compared the v2 and Jay's lens, since i simply assumed they were very close, and seeing my old results, they evidently are...


But anyway, these numbers are not really representative of the average results. In all cases, i have saved the highest and the shortest wavelength diodes of all types for experiments with lenses (and for my favorite personal lasers), and anyone who read the Custom Lens Project-thread should know that the highest wavelengths get increased less than average or shorter wavelengths!

The laser FrancoG is testing at the moment is a GGW 6x super-long-wavelength super-freak! For this reason it will again show the lowest increases with any glass lens, since a long wavelength passes plastics MUCH better.....


Once i get all three of my lenses back from Jayrob PROPERLY MOUNTED (so the imperfect mounting does not obstruct any light from passing through), i will REPEAT ALL TESTS WITH ALL LENSES, on ALL DIFFERENT DIODE TYPES I HAVE, first with one of a SHORT WAVELENGTH then with one of a LONG WAVELENGTH, so as to establish the ranges....

Since i go through HUNDREDS OF DIODES (literally), i have examples of the shortest AND longest wavelengths of each diode on hand, and this will allow me to provide the MINIMUM, the MAXIMUM and the AVERAGE power increases to be expected, with any given diode/lens combo....


Those are the final results i will post, before collecting any orders for the lenses!


Keep in mind, i do have short FL glass lenses, i even have 405nm specific coated glass lenses made to Nichia diode specs, but the lens i personally like the most is the one that wastes a few percent, but gives a rounder beam, has little or no side projections and focuses the best due to more beam volume.



Concerning the fact that Igor asked to not remove the lens from his seating, in all his threads you'll read his caution to not remove the lens to keep it clean. No other hidden reasons, and as I know that his lens P.O. gain is 26%, why the need to remove it? When you'll receive the lens to fit it in a metallic nut, you'll be surely able to perform all checks you need...:yh:

It is true that Jay will be able to do any and all comparisons he wants as soon as he gets my lenses, first imperfectly mounted and then again after mounting them perfectly in metal lens nuts himself.

Jay already said he would include his own test results after i post the ranges of increase to expect. Regardless of what diode he uses, the numbers he will get will be within the ranges i will post (after i get the lenses back from him).


BUT!

Again, the lens we are talking about here is NOT the v2 that gave me 26% (on ONE DIODE!) during my early tests. And if it was, it would most likelly perform not much different from Jay's lens (if i had to guess i'd say they would either be spot on or within 1-2%). But we will know that after it is properly mounted and tested on the SAME DIODE of the SAME WAVELENGTH at the SAME TEMPERATURE!



Franco: Please remember, the increases depend on the wavelength. 26% is NOT the standard. 26% is just what i got on that one high wl. diode with the v2 lens from the final custom lens batch. I have found less on longer wavelength diodes or rounder beam diodes and i have found as much as 43% on extremelly short wl. diodes with bad beam profiles! That is what i mean with a "range of increase to expect"...

You can't really compare two lenses without comparing them on the SAME EXACT DIODE. Otherwise the numbers are completelly meaningless.



But the v2 is NOT the lens that is my personal favorite. It would be, if i wanted to go for MAX-POWER...

Luckily Jay has already taken care of the people who want Max-Power, while i was gone.


And this is why i now finally feel free to introduce the lens that is my personal favorite, in a "Test-Buy" at first....



It will have a few percent of power less, but a rounder beam and a nicer spot...

In my experience it will also burn better than a short FL lens like my v2, due to more beam volume, resulting in easier focusing and a "sharper", better defined focus (i need to find the scientific word for this - i think it's "depth of focus")...


The reason i call the v1 lens the "medium" lens is that it's FL and NA are in between an AixiZ lens and a short FL lens like my v2 or Jay's lens... But unlike an AixiZ lens it is glass and broadband AR coated, just like Jay's lens or my short FL custom lens...



A short FL lens with a high NA will bring everything out. My v2 custom lens CAN NOT POSSIBLY produce a rounder beam only wasting 2%. In fact i'm not even sure it wastes anything at all, since according to all the specs of diodes and coatings, the results should be the same, except for minimal differences in beam diameter, due to slightly different FLs. I won't know this for sure until Jay returns all three lenses from my final lens batch properly mounted....



In order to produce a rounder beam, the NA HAS to cut some of the edges of the diode output off! In order to produce a smaller "splash", the lens HAS to have a longer FL. The longer FL reduces the max NA possible with a certain diameter lens and the lower NA results in a slightly lower power. There is no way around it!



I will explain all this in GREAT DETAIL with drawings and photos and final test results, once i get my lenses back from Jayrob properly mounted!


At this moment, no real comparison can be done
, since my lenses are mounted in improvised mounts, and the NA of the "medium" one is lowered artificially, by the back apperture of the plastic lens nut obstructing some of the light... The final difference should be lower than 7-8%, but i don't really know the actual numbers yet! I won't know them until Jay returns my lenses!



Having said that, allow me to also explain why i had to ask FrancoG not to remove the lens from the laser....

In order to get the "medium custom lens" deep enough into the laser (close enough to the diode), and still allow to attach a focusing ring, i had to use an extremelly short focusing ring, AS WELL as mount the lens in the plastic lens-nut BACKWARDS!

What this means is, i had to put the lens with the "flat" side (it's actually a bi-convex lens) towards the end of the plastic lens nut that is usually on top... The "back" of the lens is at the end of the lens nut where the focusing ring usually attaches!

After that i had to put in two tiny rubber o-rings, and then close it all off with an opened up back-plate converted into a thin ring...

Then i had to screw the extremelly short focusing ring on the bottom of the lens-nut, which was now facing outwards.


This was the ONLY WAY i could get the lens close enough to the diode for parallel focus as well as allow attaching the focusing ring for easy focusing.


Unfortunatelly the result of this was, that the spring that usually presses against the bottom of the lens-nut was now pressing against the top of it, around 0.5mm or less away from the lens. Additionally the top side - now at the bottom, has two notches in it, probably meant for a kind of tool to grab i and turn it.


Basically, there is ABSOLUTELLY NOTHING preventing the spring from touching the lens. One slip during mounting, and the spring could easily scratch the lens or it's coating!

I always had to take UTMOST CARE when mounting this lens, in order to prevent this from happening.



And since this is the ONLY example of this lens that i have, and it cost me a lot of money, i thought i'd rather ask FrancoG not to remove it from the laser, since he could accidentally cause damage to the lens upon reinserting it...

Additionally proper power comparisons would have been hindered by the fact that the laser i sent him is an extremelly long wavelength one, not to mention the fact that the lens is imperfectly mounted and some light is getting obstructed from passing through.... That's why i thought there is no point in removing the lens anyway, as the benefits would not outweigh the risks (which other than scratching the lens, include getting dirt on the window of an extremelly rare super-freak GGW diode, or even breaking the window during cleaning attempts).



But yesterday i wrote FrancoG an email, where i told him step by step what to do (and what not to), in order to carefully remove the lens and then the spring, so as to be able to put another lens into my laser....


Most importantly, i asked him that once he removes the medium lens, regardless of where he puts it in again, he does so without the spring!


That way, he can now take more photos using different lenses on the SAME LASER WITH THE SAME DIODE, and also compare burning capabilities of different lenses, a test that will be very informative, coming from a laser-pyromaniac like FrancoG... ;)




It is true, that i don't want power comparisons done on a non-representative ultra-long wavelength diode, with one of the lenses improperly mounted.... I've done those tests myself, and i know i need proper mounting and diodes from both sides of the wavelength spectrum, before i can post the final results with the ranges to expect....


I do however want spot size and shape, as well as burning comparisons done on the same diode, because i know that there a few mW of power will not make ANY difference compared to the final results...


That's why i asked FrancoG to keep the laser a day or two longer to do more tests with the lenses, before returning it all to me, but also not to replace the spring, once he takes it out, so as to avoid putting my only medium custom lens to any danger.....





I hope this clears up any misunderstandings or suspicions or whatnot...

All the final results will be published AND thoroughly explained BEFORE any orders are taken for anything!



There. I hope this clears things up a bit....
 
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IgorT

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Yes, TJ, you're right, it was already settled! I just have had the opportunity to take some shots of the IgorT FIRST (and unique, actually) Medium Lens beam, making a comparison....:yh:

There is no debate or issue to settle..

They are completelly different lenses and do completelly different things.

Which results someone likes depends on their personal preference.

Each lens has it's own benefits and drawbacks, and each person has their own preferences.


I can deliver a short FL/high NA/broadband AR custom lens in a GB for ~$35, but i would first like to see what people think of the medium FL lens, which is why i'll do a Test-Buy at "standard price" for my personal favorite first...


That's all there is to it.
 
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IgorT

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MORE ABOUT LENSES:



Yeah, the correct term i was looking for is Depth Of Focus....

The definition is:
The depth of focus is the distance over which the focussed beam has about the same intensity, it is defined as the distance over which the focal spot size changes -5%~5%.

Basically, it defines the distance lengthwise to the beam, which the most intense part of the focus is spread over...



In praxis it looks like this:
- With any given lens, the closer to the lens you focus, the shorter the depth of focus is - the distance at which a laser will burn with the highest intensity is better defined.

With a VERY WELL defined focus, the laser will burn "only" at a specific distance, while leaving things just a bit further away unharmed.... (That's a part of the reason why they can do laser eye surgery without making you blind at the same time, for example!) Additionally, a less "spread out" (or better defined) focus will have a higher energy density in the focused spot - it has a "sharper tip" of the light cone....


- With the same lens focused further away, the depth of focus becomes more "spread out" over the length of the beam. The distance of the most intense spot is less well defined. The Depth Of Focus becomes "longer" (or "deeper"? :thinking:).... Because the focus is more spread out, it will also burn less well at longer distances, as anyone who ever played with a laser already knows....


- With a longer FL lens, the depth of focus is much better defined (far less spread out lengthwise) than with a shorter FL lens, when both are focused to the same distance.... This is simply because the beam is fatter with a longer FL lens than with a shorter FL lens.

In reality, what changes is just the SCALE on which "things are happening"... A shorter FL lens focused on a shorter distance will give the same depth of focus as a longer FL lens focused on a longer distance.

Basically it's like taking a fat beam from a longer FL lens focused on a certain distance and then scaling it down - the beam becomes thinner, and the distance the beam is focused on with the same intensity becomes shorter..... (I hope i'm explaining this well enough, but i realize it will require DRAWINGS for everyone to truly comprehend it all...)


- A shorter FL lens will have a less well defined Depth Of Focus at the same distance as a longer FL lens, and as a result, a lower energy density, if the power is the same, or even if the power is higher in some cases!

This is the reason people used to say that with an AixiZ acrylic lens an open can will burn better than with a Meredith lens, even tho it will only have 250mW instead of 300mW. Obviously if you use an AR coated acylic to increase the power to 280mW it will then burn even better. If it was possible to reach 300mW with the same beam diameter as an AixiZ lens produces, it would burn A HELL OF A LOT better than a 300mW laser with a Meredith lens.


- If you can get a fatter beam of the same power it will burn better than a thinner beam of the same power, when focused to the same distance from the laser. It's simply due to the Depth Of Focus and the resulting Energy Density, nothing else... (A very thin beam however will be able to burn even when focused to "infinity" due to the energy density being so high. But not as well as a well focused beam.)

The deeper (or longer) the Depth Of Focus, the more spread out the Energy Density becomes. And when it comes to burning, the power matters a lot, but the energy density matters even more. That's why people got the feeling that clear acrylic AixiZ lenses burn better than the Meredith, even tho they waste 20%!

In industrial or even military lasers, they use absolutelly MASSIVE beam diameters, so they can focus them more accuratelly for burning at a certain well defined distance and only there, and to make the cut as sharp as possible....

The further away you want to burn, the fatter the starting beam you need. Industrial laser lenses have diameters such as 25cm for example (10 inches), sometimes even more! Military lasers, which have to shoot down rockets kilometers away don't even use lenses for focusing, but gold plated mirrors instead - mirrors, that can change their shape for focusing, instead of moving the lens!


In praxis, the fatter your laser beam starts out, the further away you can make it "burn like hell", and the better defined your focus will be at any given distance....

But due to the modules we use in this hobby, the maximum lens diameter we can use is 7mm. More than that doesn't really fit anywhere.

Besides, we don't really like those fat beams that come out of AixiZ lenses that much....


AixiZ lenses have a 7mm diameter, but much of it is wasted on the edge, only just over 5mm of it is the actual lens, and the effective diameter is 5mm. As a result, the beam will have a diameter of 5mm in the fast axis (which gets clipped) and slightly less in the short axis (which doesn't).

Since the AixiZ acrylic also has a long FL, it has to be far away from the diode, and captures less of the light cone... As a result, the NA of an AixiZ acrylic is only 0.3 - and that is for reds. For BluRays it's even less, and the acrylic material is poor at passing wavelengths around 405nm. Due to the sharp transmittance cutoff at just this point, it also wastes a LOT more power with every nanometer less a diode has.



Over a year ago, when i started the Custom Lens Project, i didn't really know what to expect. In fact i did not even know what i am supposed to be looking for.

I made many expensive mistakes, and in the end i lost over $1k just to get to three good lenses (after multiple pieces of 7 different useless but no less expensive models, with the very first model, even 30 pieces of completelly custom made spherical lenses! :cryyy:).

I have not yet even seen a Meredith lens at that time! I had no clue what would happen or what it would make the beam look like!


After i learned a bit more, i started looking for aspheric lenses, trying to get a shorter FL for a thinner beam, and a higher NA for maximum light capture...


The final custom lens batch gave me three lenses, which i called v1, v2, and v3 at that time...

- v1 is what i now call the "Medium Custom Lens"
. It has a FL in between AixiZ and the Meredith and is made of a high 405nm transmittance glass with a broadband AR coating. It's a bi-aspheric lens (bi-convex). It has the maximum diameter possible (7mm), and as a result, even at the medium FL a reasonably high NA of 0.4...
- v2 is basically a broadband AR coated Meredith but with a larger diameter, possibly capable of capturing a bit more light than a regular sized Meredith, but not yet sure on this point. It has a NA of 0.55 and a FL identical to Meredith. Like the Meredith, it is a Plano-Convex lens (only one face has an aspheric curvature).
- v3 or the "Nichia Lens" is a lens designed to perfectly match specifications provided by Nichia, specifically for 405nm diodes, and is made to capture the maximum possible diode output, and waste as little of it as possible, using a wavelength specific coating, centered at 408nm. However this lens - in the same quality as the first two - cost almost twice as much. The one i have is a "low performance version", which means "refractometer rejects" or lenses that have failed the test of being capable of writing disks. I am not yet sure if this means it causes any abberations we could detect by naked eye or not, i will need it perfectly mounted by Jayrob first... It does however have the highest 405nm throughput of any lens anyone ever saw so far (or at least will, once properly mounted). It has a NA of 0.6 and a FL shorter than Meredith.


How exactly the NA's and FL's influence the beam/spot output shape will be nicelly explained by my drawings. I hope the drawings i am working on will make all this easily understandable for everyone.


But theoretically at least, each lens in the order i wrote them will have a "thinner" (and flatter) beam with a higher power (due to FL and NA being higher with each one). But for the same reason a less well defined Depth Of Focus and slightly lower burning capabilities due to lower energy density at the same distance...



Keeping in mind that we are limited to 7mm, the best burner lens would be one that would have the beam diameter of AixiZ lenses, but the power of the short FL glass lenses.

However this is impossible for obvious reasons. Since we can not increase the lens diameter, the only way to increase the beam capture is by using a shorter FL lens of the same diameter... The lens will then sit closer to the diode, and at the same diameter, it's NA will be higher - it will capture more of the light cone because of this... But as a result the beam will become thinner and flatter, and have a less well defined focus at the same distance.


Once the NA goes above 0.5, a lens captures the entire light cone of even a 405nm diode (since 405nm diodes have a NA of 0.5 or less in their fast axis), and the resulting beam/spot shape will depend purelly on the diode alone....


If you want to get a rounder beam, you could theoretically use beam-shaping lenses, but those require axial alignment to the diode, which means you can't turn them for focusing (you have to move them without turning). Another way would be to use special beam shaping optics first (directly on the diode), and then focus the already shaped output with a regular lens, which could then be turned for focusing...

The only other way to achieve any beam shaping is by using a lens with a slightly lower NA. This last method is actually the only one used in professional laser pointers, where a "pretty" round or at least roundish output is desired...

If the NA is lower just a bit, the fast axis of the diode will clip the lens (miss the edges of the effective diameter) and be "cut off"...

As a result, the fast axis will be "roundened off". This wastes some of the power (the bits that missed the edge of the effective diameter), but only the power in the very edges of the fast axis, while the center, where the output is the most intense still goes through, as well as the entire slow axis, as is evident in the photos of the spot (it looks completelly round from two sides and slightly flat from the other two sides).


Ideally - if i could afford it - i would experiment with even more different NA's, until i would find one, that does minimal beam clipping, and gets as much light out as possible, while still roundening the fast axis off a bit, while at the same time keeping the FL just long enough to keep the "splatter" hidden within the 405nm glare.
Maybe a NA of around 0.45 would be "ideal" - i don't know, i can't find such a lens anywhere...


But i do have a lens with a NA of 0.4, which increases the power a lot. More even then my initial expectations, and produces a nice oval dot, with almost no side projections visible (unless your name is Traveller or you have his bionic eyes :angel:)....


Thing is, if 405nm diodes would not have such flat outputs with nasty side projections, or rather if they were as advanced as reds, a short FL lens would give a nice round beam. If you have a short FL / high NA glass lens and have put it in a red, you already know this...

The weird side projections which people now call "splatter" were a completelly unexpected result for me. I didn't understand it at first and it worried me. I was worried what people would think about it. This was my own fault, as i still have not tested the Meredith lens kindly provided by Dave at that time! :yabbem: I did not realize, that people have already seen this "splatter" and are used to it, or don't even care....



To recap:
When it comes to lenses, power and beam/spot shape and diameter/size (after you have glass and AR coating taken care of), the only thing that matters is the NA and FL.

If one could manipulate with both NA and FL freely, one could make a lens with maximum power (NA of 0.55 or more) and zero visible splatter (by not using too short a FL).. Except for Traveller of course.... :whistle:

But due to lens diameter limitations, the NA is limited by that lenses FL.
The only way to increease the NA is by reducing the FL, if the maximum lens diameter is fixed...


Obviously we want as high a NA as possible, as we all like seeing high numbers on our meters. In this i am no exception!
But if you reduce the FL below a certain point, the "splatter" will become larger and eventually come out of hiding behind the 405nm glare (even tho it is present with EVERY SINGLE LENS even AixiZ).

Additionally, due to the fact that 405nm diodes have a very poor aspect ratio (flat output), the higher the NA, the flatter the beam coming out of the lens will be. It will become thinner in the slow axis, but due to so much more fast axis coming out, it will seem almost just as wide there....


I was used to seeing round(ish) beams with AixiZ lenses, and while pursuing thinner beams of a higher power in my Custom Lens Project, i was foolishly expecting to get beams of the same shape, only thinner and with maximum possible power...

It wasn't until i started testing high NA lenses that i started realizing what was going on and what we will really get in the end.....


I have seen a BluRay beam as thin as 1-1.5mm once, and it was seemingly completelly round, and it even came with a high power increase! Obviously that lens was of EXTREMELLY SHORT FL, but it also had to have a lower NA, since it clipped the fast axis and made the beam round.

It is possible to make an ultra-thin round beam, but not without sacrificing some power. In addition this ultra-thin beam will have very poor focusing abilities (tested) and due to being so thin, also have a bad divergence.


Divergence is another thing to consider, when it comes to lenses. You can't really have a thinner beam, without also having a larger divergence, when focused to "infinity"... The two are directly related..

Jay: Maybe this is why you thought your lens was out of focus, when Franco took spot pics at 10m distance? The beam diameter of a shorter FL lens is smaller of course, but after a certain distance it will become larger simply due to divergence. The divergence itself is another example, where it is all just about the scale....





Anyway, the lens i would like to introduce in the "Test-Buy" is the v1 or the "Medium FL Custom Lens"... (And since we won't get any quantity discounts in the Test-Buy anyway, i could also offer some v2's for comparison... Even v3's in fact, if someone REALLY wanted to have one - like for "raw" power measurements....)


The reason for that is simply that i like the way it makes the beam and spot look - it is just my personal preference. Other people's preferences may vary....

I just like how the beam is thinner than AixiZ, but still round-ish and still has enough volume to manipulate for very well defined focusing and burning.


If i put the v2 lens into my super-freak 6x, i get almost 280mW on my meter, but when it comes to apparent brightness i don't see a difference from 265mW, i do however see a difference in the beam shape, spot and splatter...



Like i said before, i am no exception, when it comes to wanting to see as high a number as possible on my meter. But most of the time, when i play with my lasers, i do it without the meter, and in those cases it is more important for me, what the laser's output looks like and how well it burns.

And when it comes to that, my personal favorite is the v1 lens.


People have different needs and wishes, some will want more power, others might want a prettier beam. Others again will want to have access to both.




This is why i believe a Test-Buy is the best idea. Let people get some and test them, and decide what they like the most for themselves. In the end the majority will likelly want both types...


As i said before, the two lenses are completelly different, and do completelly different things. Each has it's own benefits and drawbacks...

The only thing that really matters in the end is personal preference of the individual laser hobbyist....
 

daguin

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Joined
Mar 29, 2008
Messages
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It looks like someone needs to throw a sandwich into the room for Igor. He is in "manic" mode. The testing will not end until Igor collapses.

KEEP DRINKING FLUIDS, Igor

Ya gotta love that guy, doncha?

Peace,
dave
 




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