Lasermods Claims for big improvements with undisclosed mod

Lasermod has been talking about a new mod. I understand his reluctance to make it pubic, but it has really got me thinking.

I have always followed his posts, and I think he is very honest about his claims, hes jumped the gun before, with the 45mw mod (a great mod just a little overstated), and he said so. He is someone I always read becuase hes always a good read...but it has really got me thinking this time.......

I think I am probablly wrong but he mentions thermal effenicy and breaking the crystals so what about this.

http://www.rav89.dial.pipex.com/lasers/lasermod.jpg

In the image above configuration 1 represents a standard config, and option 2 is the proposed new config (based on lasermods thermal clues). The only "addition" is an airgap. The total number of surfaces and the total air path of the IR is the same. The only way this would work is if one of the conversion processes generated more heat than the other, and heat infulenced efficeicy (I know that bit is true), and that the airgap did not reduce laser effeciency too much.

Given my lack of knowledge of the laser mechanics, I am working trying to use logic and clues from laser mods text. The only other option I can think of is in config 3 below.

http://www.rav89.dial.pipex.com/lasers/lasermod1.jpg

This again seperates the thermal components in the hope that this is what Laser mod is talking about.

The orientation of the KTP can not changed (is that true), so what are the other possibilites. Bengal talked abbout changing the output mirror, can you explain how you could do this ? I always thought the mirrors were on the crystal.

Please excuse my ignorance, I am in the honey moon phase, I just want to know MORE.

All advice and information gratefully absorbed.

Gold.

Reply from Laser Mod!!!!

Thanks mate, and for the kind words.

You are on the right track, the configuration 3 looks similar to a test model I have here. :)

The mod is simple but it works - there is however a few glitches to watch out for - all will be revealed soon.

It seems the big secret is out now.
removing the glue from between the crystal section and the diode housing.
and securing it back with artic silver.
Woo hoo.. now that was worth waing for.. maybe.. put my life on hold for that.. not!

This seems to me just another way to change alignment. I am gong to give it a go anyway, but its strange no one has posted a sucess for this mod yet....

The only posts on greenlasers so far report a drop in power ?

Does anyone here have experience of using Casix MCAs in a leadlight ?

Gold

Dont know about casix sucess,
But the lasermod mod, seems to be a bit perplexing.
if you take something that needs to be cooled, then why would you affix it to something that is a heat producer?

Questions that lead to the secrets of the universe :)

Yes that was my conclusion too (see diagrams 3 above).

My guess is that the increase that LM has seen has come from better alignment, and I am sure that the laser is more stable, but I doubt much/any power increase comes from increased capacity to deal with heat (its not cooling is it).

Could there be a explanation if the beam emitted form the diode matched the dimensions of the MCA better with the removal of 1mm of glue ?

Gold

i have found many assy's are misaligned , some quite badly
if you look at the ir filter end, you can see the alignment, looks like circles off center from each other

Bengal

Is alignment as simple as making sure you have as much area avaiable, how impoartant is the orinatation of the components.

A URL for your boy http://cctv.icode.co.uk:81/index.htm...Bird%20Box%201

My roosting/nesting blue tit (sorry about the camera quality).

Regards

Gold

The optical components need to be exactly as they are in the LL . front and back reference, its the sideways alignment that is off , if everything is centered on top of the next piece, it should be better, now some may need some fine tuning. a hair this way or the other.
one thing, in your diagram, you dont have the output coupler mirror shown. if you miss this part, no workie

ps. a to-3 style heat sink fits over the mca brass piece perfectly

Do you have a better diagram showing mirrors etc....

Looking again at my images, is there an optimal ratio of KTP to ND ? Is the comprimised in anyway with budget MCAs ?

I would guess that splitting them like in my diagram 2, would be very inefficient, is that right ?

Gold

if yoy look at sams laser faq he has some excelent diagrams.
dont do anything with the crystals themselves (mca) its the output mirror and diode that sometimes need alignment.

Quote:

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Originally Posted by Bengal

It seems the big secret is out now.
removing the glue from between the crystal section and the diode housing.
and securing it back with artic silver.
Woo hoo.. now that was worth waing for.. maybe.. put my life on hold for that.. not!

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It may not seem like a big hoo-haa to you Bengal, but I can assure you every laser that has had this mod done has had noticeable differences in stability. :roll:

And, you were asking why I would fuse the MCA holder to a known heat generator i.e. the diode housing. The anwser is this - the mod is not to as much to acheive better cooling but more of to keep the temperature of the two components pretty much constant with each other. I have found that when there was a big difference between the two - that was when the stability problems started to occur. It appears to me that any expansion caused by the heat on one side is not carried over and then we have alignment problems.

Hey Lasermod

Welcome to PhotonLexicon, I look forward to your regular contributions. All your posts on CPF I have found worth reading, your images are second to none, and your documentation is excellent (much better than mine).

I would agree that your mod increasses stability, no doubt. But you have said that every pointer you modded with stage 4 increased in power, even stock 110s. Do you belive that this was down to improved alignment? I cant speak for Bengal but I guess, we were both confused as to where the extra power comes from.

I realise that stage 4 is important with regard to future diode replacement, its just the increase in power that is puzzling.

You mention that you have gained 15mw in power by switching to a casix MCA, we are trying to get a group buy togther for Casix, could you comment on your findings on the thread ?

With regard to Wyverns 110 mod, it definatly works very well (see my post in modifications). The 110 is now my primary focus, what I initally thought was too well engineered for modding, is turing out to be the ideal host !

Kind regards


Gold

Heres my 2 cents.

This mod does nothing to increase stability. Given the optics are designed to focus the 808nM into a 50micron spot into the crystal you would have to adjust the coupling to get it back to 50micron, it looks like your just collapsing the point further by pulling the rocks closer, which does nothing other than ADD point source heat load to the innermost part of the crystal set

While we are on heat load...

You are increasing the thermal coupling of the brass to the brass, not from the crystal to the brass. The rocks are sandwiched there with glue ;)

The only benefit I see here is the REVERSE application of the heat to the non linear rock (KTP, LBO? no one knows, expect cheaper) which (in larger professional systems) is heated to increase stability and efficiency of the conversion.

I would love to have seen paste applied to the barrel and a sliver of indium foil added to the rock to help pull the heat away from the critical innards of the system.

The problem being run into here is that the crystals are optically bonded. The fracture point WILL be the bond beteen the Vanadate and KTP.

There are a few other things, but this is all I can remember off the top of my head.

Welcome to PhotonLexicon LaserMod.

We are all trying to make those things better ...so we enjoy any input that may provide answers to making more green on the cheap.

We may tear apart other methods but it is all in the name of science...so take no offence if I barge in.

It looks like your on your way to better experimentation with that Arctic silver paste.
Have you considered using "Ceramique" by Artic on the crystals themselves?

A few know my secret to getting power out of these..so I wont go into much detail here ...sorry trade secret, but...

I have found by carefully controlling the diode's temperature , may it be just a large heatsink it does well...this is where the majority of heat come from...
We CAN use this to our advantage.

Also by taking advantage of some heating (just a little) I can control the temp of the crystals .. also improves efficiency...
Too bad the Vanadate is affixed to the KTP..now this we want to cool some (keep it from cracking)..but my heatsink seems to work for that too... :D

Now the kind of mod I really would like to see is provide a small pinhole on a piece of copper plate maybe a few mills thick (we dont want to change the spot focus on the crystals too much) about 50microns at the front of the vanadate where the spot beam enters... and have that sandwiched in between using Indium foil...This will help the vanadate disappate the heat better...this is the problem spot for heat..

Then we could provide better cooling or heating... the key is to control.

So, I would have placed the Arctic paste on the channel that holds the crystals ..Provide better thermal conduction ,....instead of just in-between the diode mount and crystal holder.
As right now only part of them are contacting the metal and poorly at that.
Using that CRAPPY Cement thats on them now..

Better yet use the stuff the experts use "INDIUM" foil because that paste is hard to get off of the mirror coatings and too much cleaning or any cleaning "WILL" degrade them.

Also, Be very carefull of the Diode pump optics..dont get any foreign debre or misplaced coatings inside or on thoses lenses...that will distort the spot beam..or worse yet reflect it back into the diode and destroying it.

There has been a lot of internet mis-information, I think some of it is on purpose.
Like for example..Lens orientation...(they really do go flat sides out) use a microscope "you'll see".
And output couplers on the input..."I still cant get over that one".
And freeze spray the on the rocks..."you really want to kill that diode?"
I could go on...perhaps much of this is others "like Us" are trying to reinvent the wheel and the followers mis-interpret what is said and passes that info on as the gospel.

I , One will admit , I am still learning and altho I have spent many many hours and not to mention , I could have bought a new home for the money I have spent in lasers..You would think by now ,,.. I should know all ..I dont , But I did learn a few things along the way...thanks to friends... :D

I think we all should give our thanks to Sam Goldwasser...
For putting up all that wonderful data and comprehensive reading area
called SAMS LASERFAQ
>>>> http://repairfaq.ece.drexel.edu/sam/laserins.htm<<<
That must have takin so much out of his other FUN time to do.

I suggest everyone spend as much time there as they possibly can...
I am always learning something new everytime I visit.
>>>Oh, you might want to thank him if you get a chance on ALT.LASER<<<<

Cheers for the welcome Marconi :wink:

Well this is my second post here are things are 'heating-up' already :roll:


Just want to correct a couple of your points Spec although you have some good points:


Firstly you pointed out a potential difference in distance between the pump diode and lasing material. I do apologise for my bad drawings but I can tell you that any distance change before and after the mod is virtually none.
http://www.greenlasers.co.uk/images/full/stage4.jpg

Secondly you asked why I would not apply compound from the crystals to the brass, well I did and said so in the mod:

Quote:

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If you want to change and have the new MCA to hand you can remove the old one now or if you simply want to improve heat dissipation further you can remove the existing MCA and clean off the old white paste. On fitting the new/original MCA back again be sure it is completely free around the edges of the old white compound and apply an even layer of AS (Arctic Silver 3) around the sides that come in contact with the MCA holder. To hold the MCA in place, mix some 'Araldite' or equivalent two-part epoxy and place a small dab between the gap on the MCA holder and leave for 24hrs to harden.

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Goldmagnet, what is it you want to know about Casix?

Hello Lasermod

Good to read you again :D

Several of us here, who have not already done so, wish to purchase some Casix crystals. As someone who has used these in Leadlights perhaps you can share some of your experiences with us. DO you think Casix is the best choice ?

Have you heard from anyone who has experienced power increases following the stage 4 mod ? I have some Artic Silver on order and hope to try the mod this weekend.

Wyvern's capacitor and your 102 SMR mod work well together on the on the 110 so that my focus at the moment.

We all hope to read you here more often, and Welcome to PhotonLexicon from me too.

Gold