Received the second component of my future project

those youtube videos does not tell you how many hours you got before the diode degrades rapidly
you overdrive the diode already and any commercial module for laser show
serious quality laser engraver has TEC cooling or does drive the diode at lower currents within specs

The 6W opt lasers engravers only have an aluminum heatsink and fan cooling it.
I’ve seen people get up to 8+ W by cooling the laser in the fridge.
I don’t think I’ll be going anywhere near that high, maybe 6-7W at most assuming the crystal doesn’t burn up at that power.
My cooling should be significantly better than what opt lasers has on their engravers anyway :slight_smile:

A little :stuck_out_tongue:
I’ve done a lot of research on lasers in the past but never owned a diode this powerful.
Safety first!

This cat’s observations about safety dated or not sure made an impression upon me. :open_mouth:

I think he’s not over-hysterical about laser safety across the board per se butt where he does gets serious I do believe he’s SERIOUS. :laughing:

http://www.repairfaq.org/sam/lasersaf.htm#saftoc

http://www.repairfaq.org/sam/lasersam.htm

http://www.repairfaq.org/sam/laserfaq.htm

And some third-party harrowing stories of laser mayhem…… :person_facepalming:

https://www.photonics.com/Articles/Laser_Safety_Little_Mistakes_with_Big/a25167

Remember, it’s up to 20x as powerful as it seems to the eye (because it’s blue).

Those goggles are OD7+ so theoretically they should reduce the 6W of laser down to 0.0000006W (.00006mW) which is safe.
That is of course assuming the laser doesn’t stay on the goggles for very long or it will burn a hole through.

Yes, OD7 is quite strong. This topic becomes interesting when you take into account that a laser can be focussed using an optic…

In the above links I posted this Sam Goldwasser sez that laser glasses/goggles which are too restrictive are actually dangerous becuz ya can’t readily see at times where the beam is projecting, ending, etc. So the propensity is to do a quick sneak peek. That’s when apparently some of these eye injuries have occurred even from people who really know better.

It appears the more powerful the laser the proper goggle fitting process encompasses some touchy fine print.

Hey I’m just glad Endy isn’t gonna invite me over to sing ‘Candelas in the Wind’ while he fires up the scary sukkah. :open_mouth: :person_facepalming:

I do everything in a closed room so as long as my eyes are safe it should be ok.
If the beam is concentrated I can still clearly see where it is, and if it spreads out past the focal point it ends up being low density and not capable of starting fires.

Fires and blindness are the main two safety concerns :stuck_out_tongue:

:laughing:

JMO, butt I didn’t like it much when it was said to me “theoretically” when it came to things that can jack me up as they handed it off to me to try out. Ya know, bang, bang things. :cowboy_hat_face:

Ok understand. Now I’m curious though about sumthing. How do you absolutely KNOW that this particular pair of glasses will protect your eyes under the power levels only you really control? I assume the supplier sez that this particular diode at this particular top power range requires this minimum level of eye protection - and presumably you believe them. Or not?

However I surmise that you may exceed that range, maybe? And if so how do you determine watt glasses covers even inadvertent mistakes?

Ok. Enuff what ifs.

PS. Fires, blindness, and loss of love life. Hmmmmm. I’m not sure this is the right sequence of priorities for me. :laughing: :+1:

They are eagle pair glasses which according to my research over on the laser forums are a top brand.
Based on that I would trust the OD7 rating is true.
If you search up the OD scale you will find that level 7 is a 10 million reduction, which brings my 7W 450nm laser down to less than 1 microwatt.
That’s a lot less than the 1-5 milliwatt laser pointers that aren’t dangerous to eyesight.
I think you need to be in the tens or hundreds of milliwatts to cause damage.

I want to try messing around with my own LEP. I am new to lasers. I have many questions maybe I could get some help with? (should I make a new post?)

The “through hole” method seems more easier to DIY compared to the “reflecting method” that the Acebeam W30 uses. I am leaning towards the “through hole” method, but am concerned with the cooling problems the crystal may have. I am not trying to set any records. I just want a decent LEP that is better than the W30, so ease of build is more important.

  • It is said to avoid back reflection. But will the lens used to focus the laser pose any potential problems?
  • If I am using “through hole” how thick should my crystal be to be most effective?
  • Is the NUBM44 a good choice even if I only use like 1W or less? Could I power it at like 1mw to just run tests and focusing?
  • What optics should I use to have very good focus? I want my optics to be reliable so I dont have to worry about another factor.
  • Could I technically buy a standard “laser engraving” module and just use it? Is there some special extra optics that a LEP needs?
  • Based on my drawing of the “through hole” method, I have a collar and a beam dump and seems quite simple to DIY. Any foreseeable problems with my drawing?
  • I am quite concerned with safety so I added a beam dump, are there other possible problems?

Price is not a concern for any components especially if it increase my chances of success.

1) if you get a proper laser lens it will be fine

2) no idea, the research papers only talk about lumens, not about intensity, so there really is no information on that yet.

3) I don’t think you can power it low enough to get only 1mW.

4) some professional grade plano aspheric lens, but that would be very expensive. Thorlabs has a 100mm one for about $1.5k

5) those 1W+ laser engravers are usually using a nubm44 and laser focusing lens.

6) drawing looks about right, except if you’re using a crystal then it will likely be only a few mm in size so you need a pretty precise mount.

7) you need to calculate the diameter of the laser beam at the lens based on the divergence, since the laser lens will focus at the phosphor and spread out afterwards in a cone. Your mirror or laser sink will probably need to be much larger.

Thanks for sharing your thoughts.

  • Regarding mounting the crystal, what ideas do you have?
  • Is it fragile like LED phosphors or something like a pcb?
  • Is there some kind of glue I could use?
  • What do you think the industry uses to mount these crystals? Even if it is mounted on a flat surface, how would it even be done?
  • I will be purchasing some crystals from crytur.cz too. Would you still stick with crytur.cz if you had the choice of something else now that you have it? What about the 3x3mm size?

An idea I thought of is to glue the crystal to a piece of thin glass.

W30 is mounted on aluminium. I would mount it on a piece of silver. Then mount the silver on a copper water block. Thinking about building one.

Wel if you go with a reflect design instead of a through design it will be a lot easier to mount, because I think they sell them already bonded on a piece of metal.
With the crystal alone I was planning on machining a copper cooling block with a hole through it and then stiking the crystal over the hole with some thermal epoxy.
No idea how it is usually done in industry.
Yeah, I would stick with crytur. 5 pieces minimum though, so it will be about $250 for the 3mm ones.

I am trying to purchase the already mounted crystal.
http://www.crytur.com/products/cryphosphor-for-lasers/

Why did you choose the bare crystal instead of the mounted solution? If you have already asked them, may I know the price of the already mounted crystal?

After doing additional research, I will be going with the reflective design. A crytur rep gave me some general direction (reworded myself):
Power is unlimited as long as crystal is below 250degC
Generally, a transmissive design should be under 10W per mm2
Generally, a reflective design can be around 25W(a guess based on wording of reply) per mm2

Here is a 2018 test I found comparing reflective and transmissive

A few other articles also show that an issue is thermal management.

I have a nice high res thermal camera, do you think the intense brightness would affect the readings of an IR camera? It would solve so much guess work if I just tune using an IR camera.

Since power is not the limiting factor like LEDs, we can just keep pointing more lasers at the same spot. I was wondering if a wavien collar would prove as beneficial as it is to LEDs.

An IR camera ignores any visible light by the lens/filter just mid IR is passing to the sensor, so if the camera is rated like 350 or 550°C it can handle that temperature on the sensor

That is good news. However, I wonder if the IR camera will ever have any chance to pick up a 0.15x0.15mm spot. If there is no choice, I guess I just need to burn holes and then turn down output by some percentage.

Depends on resolution optic and focal distance, usually mor than just the laser spot will be at a relative hot temperature

My Fluke can focus down to 15cm and has 3.39mrad at 160x120 pixels, so on 15cm one pixel is 0.5mm with 22.5 °H x 31 °V FOV
A 640x480 with 15cm and same FOV has a resolution of 0.125mm
320x240 0.25mm