GB: PL520 murder fund

[Trevor]

Wouldn't you be able to get a similar effect if you used a large pelteir(TEC) unit? AFAIK those things can get pretty damn cold if you give them good enough cooling. Hook a large 200W unit up to a CPU water cooling block and you should be able to get that thing pretty damn cold. Plus the rig would be safe and highly reusable.

If you go that overboard, you'd probably need to do a nitrogen purge of the laser head... otherwise you'll get condensation and ice crystals everywhere.

Trevor

 

[mhemling33]

Where do I find liquid nitrogen?

I still have one diode, the other was sent to Dave for decanning then to Blord for the macros

I was wondering the same thing after I posted that.... and I think Liquid nitrogen would be cheaper then a large TEC set-up but i have no idea.

 

[ApexProxy]

You could seal the laser itself and the LPM head in a container that's void of moisture right?

Or go simpler/cheaper and ditch the water cooling and just use one of the bigger CPU air cooling setups. I have a small TEC setup and I found that I can keep the lenses warm by thermally epoxying resistors to them and running a little power into them. That way you prevent condensation where it matters.

 

[Trevor]

You could seal the laser itself and the LPM head in a container that's void of moisture right?

Yes; many professional laser heads are backfilled with ultra-dry nitrogen for this reason.

Driving out moisture via nitrogen purging

Trevor

 

[ApexProxy]

You are still using a one time use setup though. It would take work and money every time you want to set up a new diode.

 

[mhemling33]

while searching for where to get liquid nitrogen i came across this and thought it is a cool idea.... but maybe not for what we are talking about doing.

 

[Lazerbeak]

Just make the sight! mhemling

~ LB

 

[Trevor]

You are still using a one time use setup though. It would take work and money every time you want to set up a new diode.

You'd still have to nitrogen purge the large container with the laser and LPM; would probably be less annoying (and less costly in terms of the expensive ultra-dry gas) to just use a head with a valve and o-ring.

In either case, you can't really reuse the gas.

Trevor

 

[Blord]

I still have the second diode. If I have liquid nitrogen then I could perform the test.
But like Trevor said the condensation and liquid could destroy the optic cavity.
TEC is no problem but I can't measure the wavelength change. This test was already done by ARG.

 

[ApexProxy]

You don't think sealing the lens in the diode module and then heating the lens very slightly to prevent condensation would be enough? I found that it works pretty well in my small setup sometimes I don't even need to warm the lenses because the output of the laser itself is enough, especially when talking about 3.5W+ of 445nm

I recall ARG's TEC tests but I'm talking dropping that sucker down extremely low XD

 

[Trevor]

You don't think sealing the lens in the diode module and then heating the lens very slightly to prevent condensation would be enough? I found that it works pretty well in my small setup sometimes I don't even need to warm the lenses because the output of the laser itself is enough, especially when talking about 3.5W+ of 445nm

The laser diode window would also accrue condensation and ice crytals (defeating the purpose of heating the collimator), as would every single other cold surface in the humid environment.

Trevor

 

[ApexProxy]

Hmm, I guess that's true. I don't have a large enough power supply yet to get my TEC unit up to full power so it doesn't get to that insane cold point. In fact I believe the diode itself remains somewhere near standard room temp under full load.

 

[Trevor]

Hmm, I guess that's true. I don't have a large enough power supply yet to get my TEC unit up to full power so it doesn't get to that insane cold point. In fact I believe the diode itself remains somewhere near standard room temp under full load.

EDIT: I'm an idiot. Thought you were referring to the general setup, not yours specifically. I'd delete my post, but someone might find the information useful.

If the diode temperature stays the same, the output wavelength won't shift.

To get the wavelength to shift, you have to greatly lower (or raise, but that's not the point here ) the temperature of the laser die - it cannot maintain "room" temperature.

This chilling will lead to the diode window or worse, the die, being covered in condensation and then in frost as the temperature continues to drop.

Trevor

 

[mhemling33]

Just make the sight! mhemling

~ LB

Still playing with DPSS right now

 

[ApexProxy]

EDIT: I'm an idiot. Thought you were referring to the general setup, not yours specifically. I'd delete my post, but someone might find the information useful.

If the diode temperature stays the same, the output wavelength won't shift.

To get the wavelength to shift, you have to greatly lower (or raise, but that's not the point here ) the temperature of the laser die - it cannot maintain "room" temperature.

This chilling will lead to the diode window or worse, the die, being covered in condensation and then in frost as the temperature continues to drop.

Trevor

That makes sense. I'm thinking of the setup is sealed well enough you may only have to purge the space inside the diode module cavity since that's the only place condensation really matters right? A little arctic alumina epoxy on the back of the diode would prevent any possibility of condensation on the diode pins as well.

@mhemling33 for me, DPSS died when the PL520 was released. Now the only reason I may purchase a DPSS would be for another exotic wavelength like 473nm or for super high output 532nm lasers.

 

[ARG]

Wouldn't you be able to get a similar effect if you used a large pelteir(TEC) unit? AFAIK those things can get pretty damn cold if you give them good enough cooling. Hook a large 200W unit up to a CPU water cooling block and you should be able to get that thing pretty damn cold. Plus the rig would be safe and highly reusable.

I chilled em to 5 or 10 in my test, don't remember.

Condensation was a problem.