250mw red to white flashes.

[Scriabin]

Incandescence can always appear, but in this case I think that the oxygen is involved because the power is too low to make a such brighter incandescence without the helping of combustion.
I would try but for now I don't have any usable lenses :-/

 

[Benm]

How would you plan on trying? Do you have something that seals and can be filled with an inert gas, or hold a hard vaccuum?

One other way to try is with a material that cannot combust, but does have low enough heat conductivity to heat up from the laser... i'm thinking black ceramic or something similar.

Most ordinary materials will not withstand the temperatures involved even in absence of oxygen. Plastics will for example still melt and decompose, giving smoke and such even though not technically burning.

 

[Switch]

You could put a match in a sealed jar and light it with the laser, the it will consume all the oxygen.Wait for the smoke to settle and then start lasering your object(that is also already in the jar). That seems like a good idea to me as long as it won't cause the jar to implode or something :-/

 

[Amnizu]

You could put a match in a sealed jar and light it with the laser, the it will consume all the oxygen.Wait for the smoke to settle and then start lasering your object(that is also already in the jar). That seems like a good idea to me as long as it won't cause the jar to implode or something :-/

It will, there's a video of this exact thing on YouTube. It should be fine provided you don't use a plastic water bottle (they did).

 

[Switch]

I saw another video of a guy who lit an entire match box inside a closed jar(top down) and it jumped off the ground.

 

[Benm]

I guess you could get rid of some of the oxygen that way. Match heads do not consume any oxygen however as the oxidizer (potassium nitrate i guess) is contained within them. The burning wood will use up some oxygen, though by no means all of it.

One way to try is to put some carbon (charcoal perhaps) in an oxygen-free container and point the laser at it. If anyone has some argon (for welding) laying around it'd be an interesting demonstration.

 

[Scriabin]

One can use CO2 (that's relatively inert) for this purpose. If you don't want to burn anything inside a closed jar, you can make a reaction bethween CaCO3(or CaHCO3-sodium bicarbonate) and HCl(or other strong acid) to make pure CO2 which can be used to fill the jar with a small tube.

 

[Eudaimonium]

You are getting off the topic here
I have a DIY laser (diode from dvd burner of course) and all sort of lenses, some from burners, some from another lasers,
I focused a small dot on a dark blue electric tape, and a saw the flashes, but im my case there was white AND violet flashes.

You all started screaming 'bout some weird SCI-FI s*it, like, megawatts and all, I mean c'mon it bullshit, there might be some megawatts in that vid, but there are not in our homemade lasers, now are there?

So, what I'm screaming is, I support the plasma theory, and also adding my oppinion(s):
1.
These flashes do not appear in mid air, only when we burnin s*it, because when focus point is in mid air the laser goes right thru it, right?
It appears when the focus point just a little above the material, because the air above material (that is being thermal tortured) is hot, and while the focus point is in that hot air, it makes the air even hotter, therefore makin tiny:
1.1 plasma
1.2 electrick dicarge
1.3 (most probaly) miniature furnace, because particles in air from burned material get in the focal point

2. burned material gets on fire, but for a very shot time, ignited by (I donno how many degrees, measure it ) high temperature in this tiny small dot, more likely making it insta explode (explosion is ultra fast burning process, burning is ultra fast oxidation process), this could also explain why it doesnt happen over black metal and stuff like that

3. I can partially explain this, but I thinks it has something to do with diameter of the dot; if the diametar is exactly as wide as the wavelenght of the light, electrons start hitting eachother in rapid succesion, and big explosion is created (big, well, scaled) supported by the particles released by burning material.

Here that are my thouths, if anybody can further explain this (even better, prove it) please do so.
I'm totaly into this, I love all this misteria c*ap

 

[Switch]

I don't know if you read through the whole thread, bu the phenomenon was explained pretty well.We weren't getting off topic, but the thread has 6 pages.We were simply moving on something related to it: flashes in mid air which are indeed plasma(and no , the laser doesn't just go right through) as opposed to the white flashes created by our red lasers.

Anyway, this is a pretty old thread, but we appreciate the fact that you are indeed reading around after all.

 

[nikokapo]

I saw another video of a guy who lit an entire match box inside a closed jar(top down) and it jumped off the ground.

why arent you posting the link!?!?!!!!!!!111111111eleven



also, i've heard that if you push a red diode A LOT you can get green light from it (i dont know how or why, a friend read a lot of stuff from google when it was laser day and he said that in the first story (of the inventor) it said that (or somewhere else).....dont know if i can trust him though....but i'd like some explanation )

 

[Switch]

Well they didn't have diodes back then, maybe he just read something else, or maybe he's trying to make you burn a whole lot of diodes.That would make a lot more sense to me.Let's face it, if red diodes could produce green by accident, how hard can it be to make diodes that produce green on purpose? Red diodes emitting green = (at least)95% BS :

I can't find the video , but it's there somewhere.....I stumbled upon it again a few days ago.