general purpose optics equipment?

[coppercone2]

what if you had two lasers that are connected in parallel with a photocolor sensitive thin film (like glasses for sunlight) in the circuit that is sensitive to one of the lasers. then if the power level increased both lasers would get brighter and the mirror would get disabled? And the only way to run it would be to close one of the lasers off with like a lens cover

but it does assume a laser remains functional

[coppercone2]

Also how are those safety glasses made?

Is it safe to buff out small scratches or do they have thin films on them? The cheapo ones I have look like its a car wrap type deal (saran wrap type coating over normal acrylic glasses), which makes them unsuitable for scratch removal.

But like a thor labs one. is it a isotropic material or layered?

no one takes laser safety more seriously then a sardukar

[coppercone2]

and for visible light that you might encounter with most lasers unless its red which is boring anyway,

the thorlabs LG10 and LG12 are ok?

LG3 is cheaper but it does not block the infrared rays, which might be present if you are trying to make colors with mixers... so I think that one is out.

They really charge a god damn arm and a leg for the LG12 that have high IR cutoff.


ANd lets say one day you make a yellow laser or whatever thing like that. What should you use for that? A pink lens?
LG15 is the only one I can find. The transfer function looks kinda dodgy. There is no glasses with a brickwall response between say above 500?


I wanna know what to keep my eyes open for deals, assuming I don't want to use chinese shit I can tell that getting all this stuff together at a reasonable price range is going to take a while and be a side project.


ALso what is the best frame? B looks comfortable. B or C I guess, it reminds me of hypertherm plasma cutter goggles. I like those alot the standard frame makes me feel like budget university physics lab. The stock version looks like it might not get stolen by children but B and C are gonna disappear IMO. A looks like it will make you feel uncomfortable with heat. i know I need to make the right decision here because uncomfortable goggles are a good reason why people don't wear eye protection.

Well C look good but realistically I won't be doing laser adjustments under the floor of a C130 darpa plane so I don't think I need the strap. Any input on B?

I can see if your making things that convert color it might get pretty ridiculous with the safety requirements if different colors appear in different parts of the circuit lol

[DavidKo]

What you mean with color lasers? That "does not make sense" since for wide spectrum you need fs laser - forget it you do not have money for Alexandrite crystal rod. For tunable lasers you can use Rhodamine 6G - it was used in past, but is highly toxic and you do not work with it; it is usually pumped with second harmonic of Nd:YAG.

If you do not care about transversal mode of the laser you can use laser diodes. If yes, than in visible spectrum is He:Ne (risk to buy old one - sealing of the mirrors usually fail after some time) or Ruby laser (history - it can produce only pulses, never seen one running, only historical laser rods). Most affordable is diode pumped Nd:YAG, in school we have had some setup with standalone rod and we have build an exterior resonance chamber, but such a system is in IR @1064nm.

Easiest and most affordable is to use DPSS Nd:YAG with second harmonic generation (green laser pointers works the same way), but be careful since as was mentioned there is usually no blocking filter for 1064nm nm of Nd:YAG and this light passes directly to the retina in full power. Gas discharge lamp pumped solid state lasers uses high voltage and high power together with active water cooling and have low efficiency - definitely not recommended for beginner. Gas lasers uses high voltage - He:Ne or CO2 are common, but CO2 is 10,6um which is far IR and needs special optics; before fiber lasers and high power laser diodes they were most common lasers for industrial use.

Regarding safety - price of glasses is high and they are certified only for certain wavelengths and power. They are made from solid glass, which blocks the required wavelength. Usually one for "green" are blocking also IR light from Nd:YAG since it is common issue that second generation does not work and you have all power in IR. Forget about interference filters - you can damage them with scratching - they can be used in system, but not as a safety measure.

Corrected the Nd:YAG wavelength - it should be 1064nm 

[CatalinaWOW]

I will repeat.  Think deeply.  Your suggestion of using paired lasers with one monitored by something like the sun darkening glasses.  Have you thought about how long those take to darken?  When I was young those used to take minutes,  fifty years later it is still many seconds. 

Did you understand every sentence of what DavidKo wrote?  If not you probably shouldn't be inventing new concepts in laser safety.  Lots of homework to do first.

Laser safety goggles are not cheap.  How much is your vision worth?

You do have to set your own standards.  Maybe you can get by with enough layers of alternate protection.  Multiple physical barriers.  Multiple power lockouts.  Safety glasses are just one layer of protection, not a magical thing that automatically makes your eyes safe.

[DavidKo]

You do have to set your own standards.  Maybe you can get by with enough layers of alternate protection.  Multiple physical barriers.  Multiple power lockouts.  Safety glasses are just one layer of protection, not a magical thing that automatically makes your eyes safe.

And I completely forgot to mention that laser beam of Class > 2 can be dangerous even at diffuse reflection - for example looking at the beam on the wall, light reflected from previously ablated surface etc. Beam stoppers are not easy to create when we start to speak about high power. Every surface (nothing is black body) have Fresnel reflection - ordinary glass reflects cca 4% of light on each surface for perpendicular beam. Bigger the incident angle bigger the reflection.

@coppercone2 The Thorlabs glasses are good for laser pointers. Real safety glasses need to be enclosed like the one for brazing. No light should get inside. Something like this. Expected cost will be in thousands of EUR/USD because such a lasers should be working enclosed with lockouts as mentioned by CatalinaWOW. Opened laser systems are used only in scientific applications.

[LaserSteve]

Thorlabs glasses are common in most labs in the US.  Especially in the comfort style and the "modern goggle style.  Both of which are certified.

       While full wrap-around is still available,  it is rare these days.  I've used Thorlabs glasses in some very high power labs, you just need to match the energy ratings to the need.  Philips Laser Safety is an alternative.

Plastic lenses with testing and certification have made huge progress in the last ten years.

 What is scary is some of the cheap E-Bay glasses, I've tested more then one model to find it rated OD6 yet have 90% transmission at the designated wavelength.

Steve

[coppercone2]

I can put that on the class VIII nuclear chemical laser roadmap. Unlike the Czech republic, I am not building a death star.

[LaserSteve]

At one time, in early history,  there was a CLASS V classification. 

    Having had the privilege of working on some still manufactured "Eastern Block" very fast single pulse  lasers, I can assure you, the Eastern Block not having a Death Star was not for the lack of trying.  I won't mock them with comments ending in "Ski" as the old senior scientist I met was a wonderful teacher,  knowing hands on skills as well as having the equal to two  western PhDs in physics and quantum mechanics.  It was highly educational to have thirty minutes with him on a manufacturing floor in his new job.    Sadly from a modern point of view, and thankfully from a  lets not make War point of view,  they never quite had the ability to make  some high speed widgets the Western Block did. That  hampered implementation.    They certainly knew what they needed, but weren't there yet.   One of the work arounds for creating short pulses, was incredibly well developed, simple, now exported, and fun to use in lab situations.    I have privilege  of the visiting the plant for a past employer.  It's now in a NATO block country.

Steve

[DavidKo]

Maybe somewhere are still Nd:Glass rods (glass was easier to produce in big blocks compared to Nd:YAG monocrystals) which was intended to be used for death star configuration . They have moved them a lot without making the final laser, but in the mean time Czech Academy of Sciences get the chemical Asterix laser from Germany. We had been in Eastern block, who had one of the firsts Ruby lasers. It was incredible story how the professor smuggled one rod from US conference in his shirt breast pocket and the beginning of lasers in former Czechoslovakia. With diode pumped lasers everything had changed. The high power lasers are now easier to build and have significantly better efficiency compared to ~0.5% with discharge lamps pumped lasers and low voltage required - the biggest thing was how to deliver kV high current pulse with short ramp to the lamps. Transmission lines was used to deliver energy and switching was done by thyratrons and on some lectures were mentioned even krytrons. Second issue was how to cool such a systems due the inefficiency - Nd:Glass lasers had easily overheated and it seems that chemical lasers are the right way. In industry the fiber lasers are replacing the CO2 lasers.

Some people which had worked on LAGEOS project had holes in their retina. Never had heard what had happened in clear words (it happened at our station in Helwan, Egypt). It was somehow "classified" and people did not want to speak about it. Similar was the info regarding first person in Czechoslovakia which had received cataract treatment with Ruby laser in Soviet union (he knew personally the person doing that, laser community was small in that time) - it had hurt since it was only Q-switching.

[coppercone2]

how is a HP current source power supply for laser diodes?

I don't mean a PSU used as Current source, I mean a "current source"

I think their mad well built. Its like a harrison supply got put through star fleet boot camp

I just need to hook up a oscilloscope on very fast time base to see what happens during power up on various loads right? maybe some power LED to simulate the laser transfer function etc

[DavidKo]

For laser drivers is most important not to overshoot the current. The laser diodes do not like it.

[coppercone2]

Well I got the Thorlabs UV glasses.

I can see more and they block way more then the China glasses. And the are 10x more comfortable.


I see if you wanna work with a laser correctly, you should get band specific goggles for the frequency you are working with.My suggestion is to take it slow, save money and buy the optimum safety equipment. Seeing more makes the work more enjoyable and pleasant also. As usual, trying to be frugal ends up making you feel like the victim of a joke.


same as butter knives, you don't wanna be using the plastic butter knife from macdonalds to make toast.

[CatalinaWOW]

Well I got the Thorlabs UV glasses.

I can see more and they block way more then the China glasses. And the are 10x more comfortable.


I see if you wanna work with a laser correctly, you should get band specific goggles for the frequency you are working with.My suggestion is to take it slow, save money and buy the optimum safety equipment. Seeing more makes the work more enjoyable and pleasant also. As usual, trying to be frugal ends up making you feel like the victim of a joke.


same as butter knives, you don't wanna be using the plastic butter knife from macdonalds to make toast.

Once more proving the universal truth.  Labor can be substituted for capital, but sometimes the amount of labor is astonishing and/or unbearable.  The right equipment makes any job easier and safer.  The other thing that has been demonstrated here is that the limits on capital are always fuzzy.

[Conrad Hoffman]

You might like looking at back issues of Laser Focus magazine. Lots of lab setups shown. When you see something that looks similar to what you think you need, it's usually not hard to figure out the specifics.
https://www.laserfocusworld.com/magazine

[coppercone2]

i guess its one reason to keep dragging your ass to work

[coppercone2]

OK i got some collimator lens and a diode mount that sits diodes in a place where I can attach a little heat exchanger to them do temperature control for experiments (copper)

the prices are not people friendly (and fuck europe shipping!!!), but getting the emitter section and safety right, lets me allow for messing around with the subsequent optics, hopefully at a much lower cost. (adjust prisms, mirrors, screens, etc), hopefully maybe with some scavanged and DIY stuff. I have a bad feeling about the cheap chinese mounts and optics, as simple as it seems. at least the first stage will be quality and I can maybe identify or qualify subsequent parts if I have confidence about the first part

Building your own laser diode mount seems akin to building your own power supply chassis, which is a bit much for beginners. I hope the thermal contact surfaces will be good and that it mounts well and is more stable then something I can put together myself, that I will not need to fight with a tapered, oval or otherwise messed up bore for mounting diodes. That will probobly end with buying a special reamer and lapping tools lol


I can also do some testing on the electrical supply and hookup method with cheap diodes before I start getting optical system elements. I want to standardize the electrical hookup in my own way

also trade the steak for a baked potato to pay this expensive ass shit off. glad i did not throw away that old potato, its actually fine to eat. and I spent the entire week sharpening damaged ass kitchen knives so I don't buy that new set I was planing on