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Distance burn explanation

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Howie923

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Hey I’m new to forum but have read as a non member for a while I’ve seen this question asked before and idk why no one can give a clear answer.
What wattage, diode, lens, wavelength ect is best for distance burning.

when it comes to what’s being burnt i understand Different colors absorbs different lengths. What wave legth is best absorbed into what color at far distances. What diode and lense or beam expander will keep my diameter the smallest.

also for my specific application I would like to know what ir wavelength would be best. I want to be able to set fire to brush piles with gas on them from a safe distance. I also gave a ir scope and would like to experiment with using it idk if the wattage to burn would over expose the sight tho?
I currently use the Zeus x 7w 445 with 3x beam expander and have experimented with my 500mm telephoto lense. This works but the line profile of the 7w diode and keeping it steady from far distances is tough. Please don’t tell me about danger I grew up Around this stuff I’m not an idiot it’s just a waste of time. And as for variables let’s say I put a piece of flash paper in the pile and I can’t paint it any color.
 



Howie923

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I kind of was expecting that response. You’d think you could come to a forum full of laser enthusiasts that claim to be knowledgeable and get a straight answer but they all just give you a million reasons they can’t answer and act like there not gonna tell you or your undeserving when in reality I’m starting to figure out they honestly don’t know. I also sense a lot of people jealous when someone new mentions an expensive over kill product. I feel like I’m asking a nerd a simple question about like mine craft and he’s basically responding with “you wouldn’t get it.”

I get ur joke but like can’t anyone give an honest answer?

I guess if you want anything done right you gotta do it ur self. luckily I killed it in the crypto game before the doge crash. I’ll just have to buy the then all and do the experiment my self and be the first one able to give an answer to this.
Unrelated I build guns and there way more dangerous so please don’t hound me. But I’m working on a new build that’s gonna have two 7w 445’s. One clamp for the tripod adapter mount. then put a picatinny rail on that. mount the other laser with a adjustable dopage windage mount. 10x beam expanders. mounting the two rectangle beams in a x and then putting a site on top of all that. Looking into corrective cylindrical lenses to. If your wanna see pics when it’s done let me know. If you wanna tell me how dangerous it is let me know.
 

CurtisOliver

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You obviously haven't been looking hard enough. People have answered this sort of question many times over the years.
Distance burning is about maintaining power density over a large distance. You can throw as many watts out as you like, but if you have it diverging like a collimated torch then good luck burning anything far away. Divergence and beam specs become more important than laser output. Power then follows. Wavelength is the least important aspect.

Different colours absorbs different lengths??? Not really sure what though path you are on here.

Wavelengths only comes into play when the material you are burning has better absorption at different parts of the spectrum. Don't use a green laser on a green object for instance. The wavelength itself doesn't affect how far you can burn. You will just find that certain common wavelengths come in different lasing tech with their own properties.
 

Encap

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If you actually want to burn things, generally you would be much better off with a box of kitchen matches than a laser. There are no generalized answers to your generalized questions---laser and laser light does not work the way you imagine.

Obviously you don't know what lasers do, can do, and cannot do + what laser functional characteristics matter and what characteristics of the target matter. The "burning" you are imagining is much more complicated than what you are daydreaming about/imagining which is not going to burn anything at a distance. Especially with 2 overpriced low quality Zeus anything.

A 10X beam expander won't help you burn things at a distance will just reduce the power density 10X but it will help you put and see a smaller dot on something far away. To think otherwise is imagining/imagination not physics of lasers and laser light or causing something to heat up when exposed to a laser beam.

As a rule, the more you expand the beam, the weaker the beam gets and harder it is to burn something a 10X bean expander wtill reduce the power density over a given area by 10X and be 10X less possible to burn anything.
Example: Disregarding diminished power and aberrations cause by any lenses used for a moment, if you were able to focus 10 identical 7W 445nm lasers with 10X beam expanders on exactly the same spot not even a mm in front or behind the spot at a distance you would only have the power density of a single 7W laser without a beam expander and only at that exact spot/location.
Using a multimode 7W 445nm diode though the expander reduces the divergence but you are starting out with a fairly high amount of divergence, as lasers go when using a high power blue multimode diode, and even with an expander the beam spreads out much further at a distance.

Power density is key, the amount of output power, the divergence, how far away the target is, and how much the beam is expanded with a beam expander ---all effect the power density. The easiest way to burn something is to have a small diameter high power beam, especially if it is focused to as tiny a spot as you can get.

Is important to understand/know/recognize that a laser beam has no temperature - there is no inherent "temperature" to a laser beam. Heat is the random motion of matter particles (atomic or molecular particles).
A laser beam itself is not made of matter but of photons, which have no mass, thus a laser beam can have no temperature.
"Heat" is caused by a laser beams energy being absorbed by a materials surface and turning light energy into heat energy.
"Burning": depends upon the ability of the target to absorb and convert the laser beam energy of whatever wavelength and output power to heat.
 
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RA_pierce

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I’ve seen this question asked before and idk why no one can give a clear answer.
Because, as you said, there are lots of variables, "ifs," "buts," caveats, etc.
Contrary to what sci-fi movies indicate, lasers are almost never the most practical solution for a problem, including use as an incendiary device.

Instead of complaining about the content of the forum, maybe do more research yourself, like many of us have done.
Spoon-feeding answers gets old quickly and makes us grumpy, so requesting the spoon will get you smart-ass responses.
 

RedCowboy

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Hey I’m new to forum but have read as a non member for a while I’ve seen this question asked before and idk why no one can give a clear answer.
What wattage, diode, lens, wavelength ect is best for distance burning.

when it comes to what’s being burnt i understand Different colors absorbs different lengths. What wave legth is best absorbed into what color at far distances. What diode and lense or beam expander will keep my diameter the smallest.

also for my specific application I would like to know what ir wavelength would be best. I want to be able to set fire to brush piles with gas on them from a safe distance. I also gave a ir scope and would like to experiment with using it idk if the wattage to burn would over expose the sight tho?
I currently use the Zeus x 7w 445 with 3x beam expander and have experimented with my 500mm telephoto lense. This works but the line profile of the 7w diode and keeping it steady from far distances is tough. Please don’t tell me about danger I grew up Around this stuff I’m not an idiot it’s just a waste of time. And as for variables let’s say I put a piece of flash paper in the pile and I can’t paint it any color.

Your 7w zeus has awful divergence unlike a 7w dpss which when operating in TEM00 can produce a nice Gaussian beam needing no more than a good beam expander to reach out and light your flash-paper but the laser diode in your Zeus was designed for pumping phosphor as efficiently as possible but not so much it's coherence length so it's being a multi mode laser diode is ok for it's intended purpose but not great for focusing to a small spot over distance, one axis of your zeus beam diverges much more aggressively than the other making your far field spot in actuality a long bar, that's the 1st thing you must correct for if wishing to obtain a small spot in the far field.

p.s. Always remember to wear your laser safety glasses that attenuate the wavelength you are working with and never allow a laser beam to be directed towards people, windows or vehicles of any kind.
 
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Howie923

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You obviously haven't been looking hard enough. People have answered this sort of question many times over the years.
Distance burning is about maintaining power density over a large distance. You can throw as many watts out as you like, but if you have it diverging like a collimated torch then good luck burning anything far away. Divergence and beam specs become more important than laser output. Power then follows. Wavelength is the least important aspect.

Different colours absorbs different lengths??? Not really sure what though path you are on here.

Wavelengths only comes into play when the material you are burning has better absorption at different parts of the spectrum. Don't use a green laser on a green object for instance. The wavelength itself doesn't affect how far you can burn. You will just find that certain common wavelengths come in different lasing tech with their own properties.
That’s what I was talking about like same color beam on material. Is there an equation to figure out the absorption rate? Beam nm vs what nm the object is reflecting? Reading thru past posts you get a mix of answers and everyone wants to say there’s to many variables. And I totally get divergence I’ve used my telephoto 500mm to get it tiny. That being said having a multiple w out put on my laser it definitely burns quicker at the same distance and focal point when it’s on full. So I don’t get why laser output isnt deemed as a big factor? Then as to nm there’s clear evidence of different nm having different radiation or heat I’m not sure the right term. Does it come down to the diode and beam profile if you take out divergence with a beam expander? If so that’s back to my original question that no ones has clearly answered.
 

Howie923

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Your 7w zeus has awful divergence unlike a 7w dpss which when operating in TEM00 can produce a nice Gaussian beam needing no more than a good beam expander to reach out and light your flash-paper but the laser diode in your Zeus was designed for pumping phosphor as efficiently as possible but not so much it's coherence length so it's being a multi mode laser diode is ok for it's intended purpose but not great for focusing to a small spot over distance, one axis of your zeus beam diverges much more aggressively than the other making your far field spot in actuality a long bar, that's the 1st thing you must correct for if wishing to obtain a small spot in the far field.

p.s. Always remember to wear your laser safety glasses that attenuate the wavelength you are working with and never allow a laser beam to be directed towards people, windows or vehicles of any kind.
I was looking into cylindrical correcting lenses but that’s starts to get beyond my knowledge and adapters and beam expanders all in one seem impossible or idk how to calculate the distances. Does anyone know if a ir beam powerful enough to burn would overexpose ur standard ur night optic?
 

Howie923

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Because, as you said, there are lots of variables, "ifs," "buts," caveats, etc.
Contrary to what sci-fi movies indicate, lasers are almost never the most practical solution for a problem, including use as an incendiary device.

Instead of complaining about the content of the forum, maybe do more research yourself, like many of us have done.
Spoon-feeding answers gets old quickly and makes us grumpy, so requesting the spoon will get you smart-ass responses.
Well my research contradicts everything that’s posted here. The fact I can bump up the power on my laser and change out out and get faster burn clearly indicates watts matter. I’ve given all the variables to avoid those responses. The responses don’t even look at my question. I’d rather carry a pocket sized laser and some flash paper then make a gas torch and hope I’m far enough away and throw it. I have tons of tannerite and a farm in ohio you know how hilarious it be to set up a beam tapped to a tree turn it on in the woods with a friend and scare the shit out of them? Please show me anywhere in this forum where a clear answer has been given to this question? Not one question is spoon fed before the know it all’s try to tell you why it won’t work. There’s not that many consumer available hand held options to even choose from why is it so hard to get an answer?
 

CurtisOliver

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Of course power matters, it just isn't as important as the beam divergence and beam specs. Are you actually reading what we replying?
If I shone a 5mW laser with excellent divergence and specs would it burn at 500m. No, it couldn't burn at 1m. If I shone a 500mW laser with terrible divergence and specs, could it burn at 500m. No, the laser would of spread out too much. But the laser burnt very well at 1m? What does this tell you. Its not just about power, and it is not just about divergence and beam specs. It is about power density. Power and beam specs go hand in hand. However if there was any priority for distance burning, keeping the spot size as small as possible is at highest importance. Smaller spot size = higher density. Add more input power and you increase the power density.

Edit: As already explained, wavelength is not as important. Read above, no need to repeat. You tell us you are not seeing any answers, but they are now in this thread let alone across the forum. Try reading and taking the time to comprehend.
 

Howie923

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Your ideas really come across more like you want something to blind people at a distance with much more so than to "burn' or create enough heat to ignite anything as that is what your imaginings describe. Especially with your take on safety and the BS about "grew up around this stuff I'm not an idiot" and still not knowing/having a clue about how to do what you are imagining/dreaming about doing?

The above being said and notwithstanding, if you actually want to burn things, generally you would be much better off with a box of kitchen matches than a laser. There are no generalized answers to your generalized questions---laser and laser light does not work the way you imagine.

Obviously you don't know what lasers do, can do, and cannot do + what laser functional characteristics matter and what characteristics of the target matter. The "burning" you are imagining is much more complicated than what you are daydreaming about/imagining which is not going to burn anything at a distance. Especially with 2 overpriced low quality Zeus anything.

A 10X beam expander won't help you burn things at a distance will just reduce the power density 10X but it will help you put and see a smaller dot on something far away. To think otherwise is imagining/imagination not physics of lasers and laser light or causing something to heat up when exposed to a laser beam.

As a rule, the more you expand the beam, the weaker the beam gets and harder it is to burn something a 10X bean expander wtill reduce the power density over a given area by 10X and be 10X less possible to burn anything.
Example: Disregarding diminished power and aberrations cause by any lenses used for a moment, if you were able to focus 10 identical 7W 445nm lasers with 10X beam expanders on exactly the same spot not even a mm in front or behind the spot at a distance you would only have the power density of a single 7W laser without a beam expander and only at that exact spot/location.
Using a multimode 7W 445nm diode though the expander reduces the divergence but you are starting out with a fairly high amount of divergence, as lasers go when using a high power blue multimode diode, and even with an expander the beam spreads out much further at a distance.

Power density is key, the amount of output power, the divergence, how far away the target is, and how much the beam is expanded with a beam expander ---all effect the power density. The easiest way to burn something is to have a small diameter high power beam, especially if it is focused to as tiny a spot as you can get.

Is important to understand/know/recognize that a laser beam has no temperature - there is no inherent "temperature" to a laser beam. Heat is the random motion of matter particles (atomic or molecular particles).
A laser beam itself is not made of matter but of photons, which have no mass, thus a laser beam can have no temperature.
"Heat" is caused by a laser beams energy being absorbed by a materials surface and turning light energy into heat energy.
"Burning": depends upon the ability of the target to absorb and convert the laser beam energy of whatever wavelength and output power to heat.
If I wanted to blind people I could easily do that and wouldn’t be posting about it in a public forum full of people just like you who only assume people wanna cause death an destruction it there not like laser engraving or what ever you guys deem appropriate use.
Your ideas really come across more like you want something to blind people at a distance with much more so than to "burn' or create enough heat to ignite anything as that is what your imaginings describe. Especially with your take on safety and the BS about "grew up around this stuff I'm not an idiot" and still not knowing/having a clue about how to do what you are imagining/dreaming about doing?

The above being said and notwithstanding, if you actually want to burn things, generally you would be much better off with a box of kitchen matches than a laser. There are no generalized answers to your generalized questions---laser and laser light does not work the way you imagine.

Obviously you don't know what lasers do, can do, and cannot do + what laser functional characteristics matter and what characteristics of the target matter. The "burning" you are imagining is much more complicated than what you are daydreaming about/imagining which is not going to burn anything at a distance. Especially with 2 overpriced low quality Zeus anything.

A 10X beam expander won't help you burn things at a distance will just reduce the power density 10X but it will help you put and see a smaller dot on something far away. To think otherwise is imagining/imagination not physics of lasers and laser light or causing something to heat up when exposed to a laser beam.

As a rule, the more you expand the beam, the weaker the beam gets and harder it is to burn something a 10X bean expander wtill reduce the power density over a given area by 10X and be 10X less possible to burn anything.
Example: Disregarding diminished power and aberrations cause by any lenses used for a moment, if you were able to focus 10 identical 7W 445nm lasers with 10X beam expanders on exactly the same spot not even a mm in front or behind the spot at a distance you would only have the power density of a single 7W laser without a beam expander and only at that exact spot/location.
Using a multimode 7W 445nm diode though the expander reduces the divergence but you are starting out with a fairly high amount of divergence, as lasers go when using a high power blue multimode diode, and even with an expander the beam spreads out much further at a distance.

Power density is key, the amount of output power, the divergence, how far away the target is, and how much the beam is expanded with a beam expander ---all effect the power density. The easiest way to burn something is to have a small diameter high power beam, especially if it is focused to as tiny a spot as you can get.

Is important to understand/know/recognize that a laser beam has no temperature - there is no inherent "temperature" to a laser beam. Heat is the random motion of matter particles (atomic or molecular particles).
A laser beam itself is not made of matter but of photons, which have no mass, thus a laser beam can have no temperature.
"Heat" is caused by a laser beams energy being absorbed by a materials surface and turning light energy into heat energy.
"Burning": depends upon the ability of the target to absorb and convert the laser beam energy of whatever wavelength and output power to heat.
If I wanted to blind people I could already and wouldn’t be posting about it on a public forum? I was expecting this response and divergence. I have an x18 flame thrower not the Elon musk roof torch a 100ft plus napalm throwing pyro best im way past matches papa. And I’m not talking about a fixed 10x beam expander I’m talking adjustable. This is the issue you guys think everyone is stupid... I can tell you 100 percent from personal experience your wrong. My laser will ignite instantly with 10 beam expander compared to a few seconds with out and around 25 ft so you’ve made it clear your input is rather invalid based upon first hand experience. I get lasers don’t have temperature omg different wavelengths are better at transferring more heat energy then light.
 

CurtisOliver

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I am now 100% convinced you are either a fool or a troll. Or both.
If I wanted to blind people I could easily do that and wouldn’t be posting about it in a public forum full of people just like you who only assume people wanna cause death an destruction it there not like laser engraving or what ever you guys deem appropriate use.

If I wanted to blind people I could already and wouldn’t be posting about it on a public forum? I was expecting this response and divergence. I have an x18 flame thrower not the Elon musk roof torch a 100ft plus napalm throwing pyro best im way past matches papa. And I’m not talking about a fixed 10x beam expander I’m talking adjustable. This is the issue you guys think everyone is stupid... I can tell you 100 percent from personal experience your wrong. My laser will ignite instantly with 10 beam expander compared to a few seconds with out and around 25 ft so you’ve made it clear your input is rather invalid based upon first hand experience. I get lasers don’t have temperature omg different wavelengths are better at transferring more heat energy then light.
'I get lasers don’t have temperature omg different wavelengths are better at transferring more heat energy then light.'
Different wavelengths are not better and transferring more heat. Different materials have different absorption spectrums.

Do you understand what a beam expander does? If so you will know why they improve the burning range. See if you can figure out why based on the advice given.
 

Howie923

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Your ideas really come across more like you want something to blind people at a distance with much more so than to "burn' or create enough heat to ignite anything as that is what your imaginings describe. Especially with your take on safety and the BS about "grew up around this stuff I'm not an idiot" and still not knowing/having a clue about how to do what you are imagining/dreaming about doing?

The above being said and notwithstanding, if you actually want to burn things, generally you would be much better off with a box of kitchen matches than a laser. There are no generalized answers to your generalized questions---laser and laser light does not work the way you imagine.

Obviously you don't know what lasers do, can do, and cannot do + what laser functional characteristics matter and what characteristics of the target matter. The "burning" you are imagining is much more complicated than what you are daydreaming about/imagining which is not going to burn anything at a distance. Especially with 2 overpriced low quality Zeus anything.

A 10X beam expander won't help you burn things at a distance will just reduce the power density 10X but it will help you put and see a smaller dot on something far away. To think otherwise is imagining/imagination not physics of lasers and laser light or causing something to heat up when exposed to a laser beam.

As a rule, the more you expand the beam, the weaker the beam gets and harder it is to burn something a 10X bean expander wtill reduce the power density over a given area by 10X and be 10X less possible to burn anything.
Example: Disregarding diminished power and aberrations cause by any lenses used for a moment, if you were able to focus 10 identical 7W 445nm lasers with 10X beam expanders on exactly the same spot not even a mm in front or behind the spot at a distance you would only have the power density of a single 7W laser without a beam expander and only at that exact spot/location.
Using a multimode 7W 445nm diode though the expander reduces the divergence but you are starting out with a fairly high amount of divergence, as lasers go when using a high power blue multimode diode, and even with an expander the beam spreads out much further at a distance.

Power density is key, the amount of output power, the divergence, how far away the target is, and how much the beam is expanded with a beam expander ---all effect the power density. The easiest way to burn something is to have a small diameter high power beam, especially if it is focused to as tiny a spot as you can get.

Is important to understand/know/recognize that a laser beam has no temperature - there is no inherent "temperature" to a laser beam. Heat is the random motion of matter particles (atomic or molecular particles).
A laser beam itself is not made of matter but of photons, which have no mass, thus a laser beam can have no temperature.
"Heat" is caused by a laser beams energy being absorbed by a materials surface and turning light energy into heat energy.
"Burning": depends upon the ability of the target to absorb and convert the laser beam energy of whatever wavelength and output power to heat.
You probably think there’s no practical use for flame thrower but when I’m not having fun it’s used for brush clearing and agricultural reason. I have a 50bmg I shot a propane tank with an armor Piercing incinerating round it didn’t blow up you have to have the pilot kit perfect use for this laser. There’s only so many available on the market so picking wich one would be best should be hard. If you can’t answer please don’t waste time and spew lies about beam expanders. Other people will read this and think what ur saying is true.
 

CurtisOliver

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A 10X beam expander will actually reduce your initial power density by 100X, it will just allow the laser to maintain that power density over a longer distance.
 
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