High Power Laser Diode Power Supply 10W and Laser Safety

[@petevenuti7355]

NICE! , circuit well labeled and better explained in the fewest sentences than any of the hours of time wasting click bait out there. Safety well explained too! WELL DONE!

[@LesLaboratory]

Thanks! Yeah, short and sweet is sometimes good!

[@dougc314]

Good build, and glad to see you explaining the kind of things that real engineers have to deal with.

[@LesLaboratory]

Thanks! 😀

[@eulemitbeule5426]

There's one additional aspect of building laser drivers like this one that often gets overlooked: You have to make sure that you can still see the display with your goggles on. This build for example can't be used with red laser diodes, since goggles that block red light will also block the light from the red LEDs on the driver-> you can't see the laser but you also don't know if it is on since you can't see the emission indicator or the amp meter. Therefore it's a good idea to use white lights for the emission indicators and colour LED displays with switchable colour schemes: If you have a red laser and goggles that block red light you use a blue colour scheme and so on.

[@LesLaboratory]

This is true, and I had considered getting blue displays, however the intended use for this build is IR pump diodes. I should have covered this aspect in the video though!

[@BrianKPepin]

I use white OLED displays for mine. Then they work with any wavelength. I do use colored LEDs for status and "beam on" indicators, but I chose colors that don't overlap with common laser wavelengths.

[@fzigunov]

THIS. Dude!! I literally hate this, we have a green Nd:YAG (doubled) laser from New Wave at 532nm and the idiots put a green LED in the power supply to indicate the laser is on! Do they even use their own product??

[@dalenassar9152]

Les, GREAT VIDEO!!! I must first say CONGRATS for covering SAFETY FIRST, and doing a great job of it!! I have a couple of those 808nm lasers with the fiber attached, and an very glad to run into this video before using them!! I like your pcb design with the dual thick traces and non-solder-mask for beefing the i-carrying capacity with a solder-coat. 'Just to get word out' even extra current-carrying capacity on higher current traces, such as kW induction heater pcb's, is easy by adding soldered-on copper cable strands along the traces...but I'm sure 'you' are aware of that. THANKS MUCH!

[@LesLaboratory]

Thanks! For sure, I have done that before ;-) I suppose you can also specify a super thick copper layer as well.

[@petergoose8164]

You're doing good work Les and quite unique content. The safety briefing was top notch (though I have no intention of emulating you).

[@LesLaboratory]

Thanks! Yeah a few people had mentioned safety, and I though pwerhaps it should be mentioned on here...

[@danriches7328]

You've triggered me into wanting to get my CNC machine done so I can build the driver for my 40W FAP fiber laser. Love your videos Les, so informative and interesting. I've been interested in lasers since I was in my early teens and I still haven't finished my ruby laser despite having two rods and enough xenon lamps to outshine the sun lol. Thanks to you I now know exactly what spec of laser safety goggles to buy which I didn't beforehand and was one reason I kept putting off the fap laser driver. Thanks again and can't wait for the next video!!

[@LesLaboratory]

Thanks! I have been thinking about CNC myself as well. I picked up an Old Domino Laser Marking head (teadown coming up!) and it has a digital Galvo scanning head, just need to build a controller for it :-)

[@danriches7328]

@@LesLaboratory ooooh galvo's, very nice! Can't wait

[@hernanbenitez5361]

Hello, Good Work with power supply! I would like to known, if you can explaind me, how regulated the voltaje in the diode? The voltage drop is 0.7 across the mosfet, 0.094 volts across the resistor. You are feeding the diode with 4.2 volts. I don't understand how the circuit regulates the proper voltage so that 1.8 to 2 v drops in the laser diode? What occurs to me, but it is very far-fetched, is that the current regulates the voltage drop in the diode, but I don't think it happens that way. Can you explain to me how you regulate the 1.8 V on the laser diode? I would appreciate. greetings and excellent work.

[@LesLaboratory]

Thanks! Diode drops are relatively fixed values. So if you had a 5v current limited supply, the voltage drop would still be ~2v, you would just dissipate more heat through the MOSFET and sense resistors.

[@hernanbenitez5361]

Thanks, yes I think you have right. I don't think about that. I will probe!

[@firSound]

@@LesLaboratory Do you happen to know of a good resource explaining why this is the case? A physics perspective would be most helpful. I very much appreciate you and your channel.

[@RobertoCiliberti-z2e]

Beautiful!! very well done. Is the wiring of the power supply available somewhere? I am really interested in replicating it for a project of mine

[@andymouse]

Awesome build look forward to phase two...cheers.

[@LesLaboratory]

Thanks! Phas 2 will be awesome, its a repair rather than a ground up build, but it will open up avenues of exploration!

[@kenwallace6493]

Great stuff. Now, are there receivers (like PIN diodes) that can convert that power back to volts & amps with reasonable efficiency? Isolated power is often needed for SiC FET drivers in HV equipment such as solid-state transformers (SST). In short a DC/DC converter with isolation requirements in the 10KV - 100 KV range.

[@DJPhantomRage]

Explains why my Lab supply is so expensive when it was new. .5 volt to 35 volts current regulated up to 40 amps. Huge rack mount beast that weights in around 80 pounds..

[@LesLaboratory]

Cool! I would have preferred a linear supply to be honest, but transformers are pretty expensive!

[@bussi7859]

Solid as allways

[@LesLaboratory]

Thanks!

[@kVital_2023]

Nice! But it seems that there is a problem (31mA drop in 52s). I would advise you to use a shunt amplifier like AD8210 or a similar.

[@LesLaboratory]

Thanks, I will look into that. The PSU does stablize after a few minutes, and after that, is steady as a rock, but I'm always keen to take advice and try new things.

[@lordofelectrons4513]

Thanks for the short but excellent tutorial on eye protection. I had wondered about this issue when you were demonstrating the tunable bye laser which must present a bit of a challenge considering the multitude of wave lengths available, how is this situation managed?

[@LesLaboratory]

It's not quite as bad as you think. You can get laser eyewear that covers a wide range of wavelengths, and most will also cover UV (but always check the data sheets!) That said, I own 5 pairs of safety glasses now for different purposes, so it's all getting a bit pricey!

[@eulemitbeule5426]

It all depends on the output power, if you're still operating in the class 1/2 power regime you generally don't need laser goggles as long as you make sure that there's no possibility that you can stare directly at the beam. For higher power dye lasers you can either get neutral density (ND) goggles that reduce the light to 1 or even 0.1%, regardless of wavelength (but are extremely dark) or laser goggles that just cover a specific band (for example 300-532 nm)

[@juniorjacka55]

I am also currently working with a 10W output fiber-coupled laser diode hoping to build a fiber-pumped laser system and I was wondering if you have your PCB board either available for purchase or if it has been made available open source so I can put one together myself? Any help/advice would be greatly appreciated as I plan on starting small pumping with only two 10W diodes and then later up to six diodes.

[@rickmally5777]

thanks Les.. ...where did you get the IR card ??...and i did not catch if mentioned the cost of the diode -r

[@LesLaboratory]

The diode was just shy of $300 USD, which is actually fairly cheap! The card came from eBay, there are sellers in China that sell them, so expect a delay in shipping, but they are dirt cheap.

[@EricNBrown]

In ophthalmology an 810 nm laser is routinely used for eye surgery at about 2 W (search for diode laser cyclophotocoagulation for information). So, yes, please be careful.

[@LesLaboratory]

Indeed. This is why I took the opportunity to discuss some safety aspects. There is a lot of crazy stuff on KZbin.

[@petevenuti7355]

😜 I WANT THAT SHIRT! (sorry for yelling)

[@ElectruinoDiy]

schematic link plzzz

[@ilyamanyakin8241]

Can you comment on grounding of chassis/box containing the controller - any tips on this?

[@LesLaboratory]

Since this a mains voltage project the metal front and back panels are bonded to earth. The Laser diode itself is not be grounded, as the cathode goes via a 0.01R sense resistor. That said, the sense resistor is a low impedance path to the negative of the supply in any case.

[@great__success]

Great video as well as presentation - that laser diode must be pretty expensive, are you planning to implement some extra voltage/current protection just in case something would happen to LM358 (maybe some highly energetical particle from space :D ) Personally I would not trust opamp that much, but I guess 10Amp might be to much for linear regulators, even for ultra low dropout....

[@LesLaboratory]

I have a Lasorb mounted across the diode for ESD and transient protection. I suppose if the MOSFET failed short I would have a bad day, but there is always a risk with everything.

[@great__success]

@@LesLaboratory probably eFuse might do the extra protection - it is also super cheap

[@LesLaboratory]

@@great__success a good point!

[@Zenodilodon]

Hey Les, I have been working on supporting laser electronics lately. I feel like we should discuss this stuff and team up possibly? I think we could make solid DIY scalable kits/modules.

[@LesLaboratory]

Cool! Sure, if you want I can send you a couple of the PCB's I have made to have a play with, but sure, let's have a chat. I am on vacation just now, but ping me an email.

[@ethanmye-rs]

Perhaps I missed it - how much did the diode cost?

[@LesLaboratory]

$298 USD including express shipping, which believe it or not is actually very inexpensive, especially at this wavelength.

[@florinpetrache7834]

can i use for mini tea laser channel, aluminium hexagonal (24mm diametter ,12cm long)?

[@whatelseison8970]

This is an ultra low voltage supply designed as a constant current source. It really couldn't be more different than what you need for that. TEA lasers on the other hand are run from low average current pulsed or AC high voltage sources (neon sign transformers, flybacks, etc.) Fortunately, I believe Les has also done videos on that type of supply and I'm sure he'll chime in at some point to point you in that direction.

[@LesLaboratory]

Indeed, please use the appropriate thread to avoid confusion. That said, it might work, though 1 inch diameter seesm a little large. I used 8mm bars.

[@WaffleStaffel]

Very nice and clean build, and great safety information. Hey, is the email address on your "about" tab valid? I sent a question about PySpectrometer, but haven't heard back yet.

[@LesLaboratory]

Yes, it is, apologies, sometimes the slip through the cracks. Give me a clue so I can find your email.

[@WaffleStaffel]

@@LesLaboratory Oh, cool. It's from "animal_model", it's about using a prism vs a diffraction grating. I don't want to come off as though you _owe_ me a reply, I was just thinking it might have gone to spam. Thanks!

[@alexeyk7018]

What about temperature control?

[@LesLaboratory]

At the moment this is just a test, but sure for DPSS pumping temperature contol is required, however it is not as critical as you might think. Diode lasers like this have quite a broad emission peak, according to the datasheet 3.6nm FWHM, with a temperature drift of 0.25nm/Degree or there abouts, you can get away with a relatively large temperature drift, compared with the temperature requirements for KTP for example.

[@mattwillis3219]

Absolutely terrifying, long wavelength laser light at power levels thousands of times greater than what it takes to permanently damage your vision is nightmare fuel. Important consideration is the optical density ratings, as given for CW lasers is only safe when the power density is not exceeded for Les your LG5 is OK when your 10w is expanded larger than 0.6mm.

[@LesLaboratory]

Indeed! Kentek's calculator assumes quite a lreg beam diameter for its calculator, where I assume a tightly collimated beam. That said, in the application I intend to use this, the beam should be inaccessible in any case, except of course whilst I am doing the job!

[@user-zq6pj5jo8j]

"iF YOU WANT TO SEE MORE CONTENT LIKE THIS.." WARE YOUR LASER SAFETY GLASSES..LOL