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How good are these optics?

nzoomed

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Im building my first laser, with an M140 diode.
Will run at around its maximum output, but I dont believe 2W output is possible unless you have good optics.

Anyway, for this unit, im installing the diode inside this housing here:

Anyone used these before? If there is something better, I may look at upgrading it in future i guess, will wait and see how sharp the beam is.
 



BowtieGuy

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Hard to tell from the pic, but that lens looks like a cheap acrylic lens rather than glass, but you never know.
I would use an G2 or G8 lens from DTR's store for assured quality and output.

Edit: For a couple of dollars more, I'd also use one of DTR's solid copper modules for your diode.
 
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nzoomed

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Hard to tell from the pic, but that lens looks like a cheap acrylic lens rather than glass, but you never know.
I would use an G2 or G8 lens from DTR's store for assured quality and output.

Edit: For a couple of dollars more, I'd also use one of DTR's solid copper modules for your diode.

Ok well seller claims its glass (i believe these are recovered out of old laser equipment)
Im not sure if the whole unit I bought is copper or not, the head looks copper, but the rest is possibly copper that has been plated.
Will wait and see I guess.

Wouldn't an acrylic lens melt?

What does a G2 or G8 actually signify?
Seller claims the lens specs are MP905x8mm, whatever that means.
 

BowtieGuy

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Yes, it does look like a copper front piece, but the seller is calling it brass, so who knows?
You're correct, an acrylic lens would melt with that M140 diode, and I'm not sure what MP905x8mm designation means.

There are a lot of good lens discussion threads here, but the search function on this new version of LPF is a real POS and nearly worthless in my opinion.
 
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nzoomed

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Yeah, I know what you mean about the search.

I guess I will see how this lens performs when I get it.
I was told these diodes dont give out too much heat, so dont know how important it is to get a full copper housing or not.
Im using a decent sized heatsink.
 

BowtieGuy

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You'll be alright with that module, it should do the job.

Be sure and share your build with us when you're finished with it.
 

nzoomed

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Yes I sure will.
I should have all the parts next week im hoping.
 

paul1598419

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My best guess is the lens is a multi-element glass lens. It will reduce the power output to some level above 30% of the actual output power. You can get single element aspheric lenses on eBay for less than $8.00 each that are close enough to the DTR G2 so that the difference in output power will be not more than 2% at most..

Since the seller has said this is a brass module I wouldn't expect it to be copper. If it is copper, it certainly won't be the very pure copper ones that I use. That could be a likely reason they are calling them brass.
 

nzoomed

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OK thats good to know, I guess I should order a one of those lenses anyway.
 

Lifetime17

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Hi.
M9 X .05 X8mm is the size of the threads on the lens barrel . M9 x 0.5 mm fits all Aixiz copper 12mm modules and you focus adapter threads .And the # 8 designates the length of the lens barrel, Go to the DTR site order a copper 12mm module that will fit the 5.6mm / M140 diode and you will have a need for a diode press tool in the 5.6mm size to press I the diode to the 12mm module. As said before a G2 or G8 lens will be best for maximum power output of the emitting diode .
The 12mm module in your thread are usually brass and that will not distribute heat as well as copper and the acrylic lens is a no no yes it will melt immediately and kill the diode window. And dont forget the thermal compound on the 12mm module before you assemble into the heatsink. This ensures that all the microscopic voids are filled and the heat dissipation is evenly distributed to the main heat sink to keep the diode cool.
DTR has all th right components dont be fooled by a lot of Chinese claims about laser components.
Sorry about being late to the party LPF.
Rich:)
 

nzoomed

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Ok that's helpful.
Didn't know I needed a special press tool either.
I use arctic silver in alot of these kind of applications. Do you recommend setting the driver in silicone adhesive too? I have a tube fujik thermal compound.
I was assuming this module was recovered out of old equipment going by the description. Will be interesting to see what it's like when I get it but will go and order a better unit I think.
 

paul1598419

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I was looking on eBay today and saw some "G2" lenses for $7.XX. Don't remember the exact price, but they are good enough to get you over 2 watts with an M140 diode driven at 1800 mA. They generally come in brass housings as opposed to the black metal housings the 3 element lenses are normally seen in. They are M9X0.5 housings, so look for ones with that light brass color if you just want to scan search for one. Then shop for the least price. These generally have a focal length of ~2.39 mm.
 

nzoomed

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Ok I mi
I was looking on eBay today and saw some "G2" lenses for $7.XX. Don't remember the exact price, but they are good enough to get you over 2 watts with an M140 diode driven at 1800 mA. They generally come in brass housings as opposed to the black metal housings the 3 element lenses are normally seen in. They are M9X0.5 housings, so look for ones with that light brass color if you just want to scan search for one. Then shop for the least price. These generally have a focal length of ~2.39 mm.
Ok I might take a look at those.
I had been looking at some G8 lenses.
Is it safe for the diode to run at 1800mA?
The maximum current for these is 1700mA and even then, that shortens the life according to the datasheet.
 

paul1598419

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At 1.8 amps, this has been the current many have used for years to drive the M140 diode. I have built over ten of these using 1.8 amp X-Drives over the years and none have failed yet, to my knowledge. There have been so many driven at this current that it is likely hundreds of builds have utilized this current. I suspect it will cause some loss of hours, but not enough to cause failures at the amount of time we use them. Unlike lab lasers used many hours each day, these pointers are used maybe an hour at most per day. So, you may lose 30,000 hours, but still retain 20,000 as just a guess.
 

Lifetime17

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Yes as Paul said many have been built with a 1.8A driver setting, actually now the driver cost more than the diodes.
Even the A140's can come into a range of 1.6/1.8Ws at a little lower driver setting . Some can do 2w's of the A140's
I built quite a few of the A140's doing 1.8/2W's for customers and no problems heard of .
Rich:)
 

nzoomed

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Yes as Paul said many have been built with a 1.8A driver setting, actually now the driver cost more than the diodes.
Even the A140's can come into a range of 1.6/1.8Ws at a little lower driver setting . Some can do 2w's of the A140's
I built quite a few of the A140's doing 1.8/2W's for customers and no problems heard of .
Rich:)
Ok. That's good to know.
I was more concerned that it might have been an exponential curve when current is increased.
Some devices can fail rather fast if run even a little bit over the parameters.
 




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