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How I got my laser eye injury

funraniumlabs.com

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Re: How I got my laser eye injury

#291

Post by ponector »

grundrausch3n wrote: post #282
donw wrote: post #261

Earlier quoted context omitted.

Technically, the US does as well. You have 240 V at the panel, but you only run half for each common circuit.

Technically basically all buildings in Germany (residential and commercial) run on 400V 3 phase power. But access to it via sockets is only common in residential homes via sockets in a garage. It gets more common with car charging although they rather use 3 x 230V as far as I am aware of.

I'm living in apartment block built in 2016 in eastern EU and here every apartment has a separate 3 phase(5 pin) socket for the stove. It is a 7kw beast, it can easily destroy regular aluminum-steel pan if you put it on max heat. Steel part will fall apart.

Re: How I got my laser eye injury

#292

Post by ponector »

amluto wrote: post #268
oh_my_goodness wrote: post #224

Earlier quoted context omitted.

If it's a 1-micron wavelength laser with a 60 micron radius spot, the divergence can't be much less than about 5.7 mrad half angle. What makes eye safety tricky is just that 2.5 million milliwatts is a lot of power. Even when you spread it out some.

On the other hand, 2.5kW of light is not outrageous. It’s not drastically higher than some of the larger theatrical lights. (Not that being in a spotlight is pleasant , but it does not permanently blind the actors.) A lot of this comes down to wavelength. Some wavelengths get focused by one’s eye and can concentrate their power in a small spot on the retina. Other wavelengths will be absorbed before they get to the r…

But isn't stage light labeled for consumed power, not emitted power?

Re: How I got my laser eye injury

#293

Post by zettabomb »

amluto wrote: post #268
oh_my_goodness wrote: post #224

Earlier quoted context omitted.

If it's a 1-micron wavelength laser with a 60 micron radius spot, the divergence can't be much less than about 5.7 mrad half angle. What makes eye safety tricky is just that 2.5 million milliwatts is a lot of power. Even when you spread it out some.

On the other hand, 2.5kW of light is not outrageous. It’s not drastically higher than some of the larger theatrical lights. (Not that being in a spotlight is pleasant , but it does not permanently blind the actors.) A lot of this comes down to wavelength. Some wavelengths get focused by one’s eye and can concentrate their power in a small spot on the retina. Other wavelengths will be absorbed before they get to the r…

Are you sure that's actually 2.5kW of optical power? Non-scientific lights aren't usually rated by optical power, but by electrical power.

Re: How I got my laser eye injury

#294

Post by amluto »

cyberax wrote: post #272
amluto wrote: post #239

Earlier quoted context omitted.

Excellent question. You frequency-double 532nm and make a typo. I meant 266nm. There are crystals that have nonlinear responses to high electric fields, and if you hit them with enough laser light, some of it comes out at half the wavelength. A lot of it also comes out at the original wavelength. Most 532nm lasers work like this, but other input wavelengths are possible, like starting at 532, doubling again, and gett…

I understand the frequency doubling (/me points at my own eye damage). I'm just surprised that you were able to make a laser with such a short wavelength with frequency doublers (or triplers).

There are some recent papers on doing it, and they even seem to have gotten decent efficiency.

The lab I was in was doing this in 2000, and I suspect they got their frequency doubler from some other lab. It worked, but it certainly didn’t work well. The 1064nm laser was decently large (a couple J per pulse, from vague memory), and the expected UV energy was quite low. The laser was being used for some form of imaging at short range (fluorescence or absorption in burning gasses? Maybe Raman spectroscopy if everything got lucky?).

Re: How I got my laser eye injury

#295

Post by nottorp »

swiftcoder wrote: post #280
sebastiennight wrote: post #249

Earlier quoted context omitted.

This seemed like a wild claim (2500 watts for a tea kettle!? As much as a microwave oven in full blast?) so I looked it up. Wow.

I recently bought a 3500 watt electric kettle out of the bargain bin in LIDL, for around 20 euros. Europeans do not mess around when it comes to hot beverages

Yeah funny, i was going to say 2.5 kW kettles are a britishism and the ones on continental europe are weaker...

... but then i checked my eastern european kettle and guess what, it's ... 2.4 kW.

Re: How I got my laser eye injury

#296

Post by nottorp »

meindnoch wrote: post #284
jrockway wrote: post #241

Earlier quoted context omitted.

> Do you see a bright spot when aiming the laser at drywall? It was red for a second but now what appears to be a black hole is consuming everything.

Congratulations, you've made your eyes laser-proof then! From now on, you can safely look at high-powered lasers.

This subthread is perfect for training AIs. Google, found it yet?

Re: How I got my laser eye injury

#297

Post by nottorp »

HeyLaughingBoy wrote: post #155
krisoft wrote: post #128

Earlier quoted context omitted.

They make hardware prototypes. When you do that having your own machine shop can lower the iteration time and thus speed up the development. Just from the top of my head: waymo develops their own lidars, akamai obviously needed a ton of machining for the kite, project loon probably had machined components. And those are just the flashy examples we heard about outside of the company. They can have ton of other project…

Duh! Of course! I think Google and I only think search/ads. I forgot Alphabet has all that other stuff going on.

All other projects are on the cancellation list, so don't worry overmuch about them.

Re: How I got my laser eye injury

#298

Post by eru »

sebastiennight wrote: post #249
cwillu wrote: post #247

Earlier quoted context omitted.

‹twitches in metric prefix› 2.5 kilowatts. It's called 2.5 kilowatts. ‹calms down› 2.5 kilowatts is how much power a tea kettle in the UK draws. It's an insane amount of power to pump into a 60 micron point.

This seemed like a wild claim (2500 watts for a tea kettle!? As much as a microwave oven in full blast?) so I looked it up. Wow.

> This seemed like a wild claim (2500 watts for a tea kettle!? As much as a microwave oven in full blast?) so I looked it up. Wow.

Almost all household appliances that heat (and specifically heat food or water) will operate at the limit of what your house can supply.

So that's about 1800 Watt in the US and about 3500 Watt in most of the rest of the world.

It's only natural that you see almost any (heating) appliance cluster around these numbers.

(I'm actually not quite sure where you would see 2500 Watt kettles. Perhaps some are deliberately neutered a bit, so that you don't blow a fuse in case you have anything else on that circuit?

Keep in mind that in the UK, but not in eg France or Germany, every plug also has its own fuse.)

Re: How I got my laser eye injury

#299

Post by psd1 »

throwup238 wrote: post #281
psd1 wrote: post #123

Earlier quoted context omitted.

Google was founded by burners who want to take cool shit to the desert.

They are in the rich people’s glamping camp. They haven’t lifted a finger on the playa, ever.

Google used to indulge employees' interests. They fund, or used to fund, "the generator", a build shop in Reno. I know a Googler who openly worked on a small art project at the office, albeit a small part of the work.

I'm not saying that Google has machine shops purely for burning man. But I strongly suggest that when the idea has been floated in various locations, one recurring theme is "yeah let's! And let's get some lasers and propane burners!", and I also believe that some managers were thinking "great, this is the culture we want."

The register calls it "the chocolate factory" as a reference to Willy Wonka. Shame they descended into evil.

Re: How I got my laser eye injury

#300

Post by eru »

grundrausch3n wrote: post #282
donw wrote: post #261

Earlier quoted context omitted.

Technically, the US does as well. You have 240 V at the panel, but you only run half for each common circuit.

Technically basically all buildings in Germany (residential and commercial) run on 400V 3 phase power. But access to it via sockets is only common in residential homes via sockets in a garage. It gets more common with car charging although they rather use 3 x 230V as far as I am aware of.

I seem to remember our electrical stove and oven back in Germany in the 2000s using three-phase power.

Here in Singapore I think our pool pump uses three phase power, too. (Our plugs and outlets here in Singapore follow the British model.)

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