Replacing a 473nm Blue's IR Diode with a More Powerful One

Got a question for all you folks.

Say you were to purchase a relativity low powered (5mW) 473nm blue pointer for say $400-$500. Is it possible to simply take the pointer apart and replace the IR diode with a much higher powered IR diode and make the appropriate changes (or replacements) to the driver?

Would the crystals pump correctly still or are they tuned in some way to the energy they are intended to convey/convert?

Well that wouldn't work very well because usally the crystals are usally pumped with the max amount of IR they can before they die.

So doing that would give it some more IR most likely killing but there is a very still chance that it will work but it's not worth the risk.

It depends upon the company. Optotronics and high end companies won't push their crystals to teh max, so you might get some benefit, but it depends on the laser itself.

True but do you really want to risk it is the question.

You will break it. They are too complicated for anyone but a factory trained tech.

Well not ANYONE BUT a factory trained tech ... http://www.photonlexicon.com/forums/showthread.php?t=6695 this guy built his own 473nm blue, and I think he's getting about 60+ mW.

You could do it, but do you want to risk breaking a $500 laser?

Regards,

Adam

I always thought that the IR diode in these more complicated DPSS lasers is actually being run at less its full capability. I thought the crystals were the big limiting factor for cranking up the power.

-Jakob

^They are typically run below their rating in higher-quality systems. Here's the shorthand: The biggest difference (but definitely not the only difference) is the coatings on the crystals and mirrors. In a green laser, you need HR@1064nm, in a blue laser you need HR@946nm. That way when you pump the Nd:YVO4 with 808nm light, instead of lasing at 1064nm, the crystal lases at 946nm (which is a much weaker line of Nd:YVO4, and requires harder pumping to obtain). One you've got the crystal lasing at 946nm, then you frequency double its output using a SHG crystal. Usually for blue a crystal like LBO or BBO is used, since KTP isn't very efficient below 500nm. This doesn't even begin to take into account the extreme precision required for good alignment.

Whether or not you can upgrade the pump diode depends on the strength of the coatings on the crystals and mirrors, since too much pump energy will burn these coatings, rendering them useless. There is a good chance that you could pump the crystals from a 5mW blue laser with a higher-rated diode and get a little more power, just don't get too greedy. You'll most likely be limited to 10-20mW of 473nm light at best..

I think I understand now...

-Jakob

pianoman2011 said:

I think I understand now...

-Jakob

Click to expand...

same here. so much knowledge here.

TheGr8Revealing said:

Got a question for all you folks.

Say you were to purchase a relativity low powered (5mW) 473nm blue pointer for say $400-$500. Is it possible to simply take the pointer apart and replace the IR diode with a much higher powered IR diode and make the appropriate changes (or replacements) to the driver?

Would the crystals pump correctly still or are they tuned in some way to the energy they are intended to convey/convert?

Click to expand...

You would probably be better off turning the pot 1/4 of a turn..

Eku said:

Well that wouldn't work very well because usally the crystals are usally pumped with the max amount of IR they can before they die.

So doing that would give it some more IR most likely killing but there is a very still chance that it will work but it's not worth the risk.

Click to expand...

Not true at all...

Most models 5-40mW all use the same exact crystals.

It really depends on who it was made by. If it was done by a good company such as CNI or Viasho, you could probably just turn up the current.

The reason being that CNI/Viasho builds lasers per order. If someone orders a 5mW blue, they build a blue (which uses the exact same components as the higher power models) and turn it down to 5mW, or just slightly over, because that is what was ordered. The components can handle much more.

To answer your question, YES (but there is nothing "simple" about it). You can put a stronger pump in and get more power BUT there is a limit. The reson you dont see 100mW+ blue pointers is because of HEAT. They need really really precise cooling to make good power. I have a 250mW 473nm blue laser and if I turn the TECs off, it wont even lase. That's how important temperature is.

So you'll get to a point where the extra pump power is actually hindering your power because of the extra heat created.


Now, this is all assuming you've done this before and you know what you're doing. If you haven't, diode alignment (especially on a blue because the lasing threshold is so high) is a pain in the ass and you will get very frustrated. Unless you've done this several times on a green laser and have gotten good results, chances are you will never get that blue working again.

The one exception here are the viasho lasers (RPL's etc). The reason being is that pump replacement on these is really simple. The entire lasing cavity pops off with four bolts and the pump is exposed. The only problem is that they dont use a variable driver, so even if you pop in a better pump, it wont be getting any more current. Also, RPL's have 2.5W diodes that are usually only running at about 1.5W. You have a full watt of wiggle room to see how much power you can get.

The bottom line is that if you really want a strong blue, buy a lab module.

I would be very weary about attempting this.

First of all i doubt there is very much to gain from the crystals in there, and you risk damaging those with more pump energy. Also, alignment of the new pump with the crystals could pose a problem. With greens this is often quite doable, but i have my doubs with blues.

You would have to try pretty darn hard to damage the crystals at all. LBO and yag have a decent damage threshold, and these same materials are used in lasers which are pumped by 5-10W or more of pump power.

Risking damage to the crystals should be the least of your concerns. Just dont get any gunk on them, or you will burn the gunk into the face of the crystal and ruin it.

Worry more about heat and temperatures in general.

But, as I've said before, dont bother modding a handheld laser. Get it into a lab host with TEC's and tune the temperatures, that is how you're going to see some real power.