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405 vs 635 burning question

Crazlaser

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Hi guys, today I received three lasers from Sanwu, two of which were a 800mw 635nm Challenger (6 days later it's dead) and the there was a 250mw 405nm. The red laser is not very good at burning, albeit bright. The 405 lights things on fire and smokes things very fast when focused, but the red laser is slower even though it's over three times as powerful. Is there an explanation? I've fully charged the batteries. :thanks: :undecided:
 
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BobMc

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Hi guys, today I received three lasers from Sanwu, two of which were a 800mw 635nm Challenger and the there was a 250mw 405nm. The red laser is not very good at burning, albeit bright. The 405 lights things on fire and smokes things very fast when focused, but the red laser is slower even though it's over three times as powerful. Is there an explanation? I've fully charged the batteries. :thanks: :undecided:
I don't know the technical answer, hopefully someone else can give you that. But as far as I know the 405 wave length is the best burning of the wave lengths. Inherently. That's why 250mw's will burn better than 800mw's 635. The 445-480ish are good burner also. I hear the 808's are real good too, but there dangerous because you can't see the beam. Hope this helps a little. Nothing wrong with your lasers it's just the way the different wave lengths burn., edit----- Hey, enjoy your Sanwu's their great units!
 
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Hap

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^Indeed. 405nm is much better at burning dark colored material than a 650nm laser would at similar power. Nothing wrong with your lasers :p

-Alex
 

diachi

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I don't know the technical answer, hopefully someone else can give you that. But as far as I know the 405 wave length is the best burning of the wave lengths. Inherently. That's why 250mw's will burn better than 800mw's 635. The 445-480ish are good burner also. I hear the 808's are real good too, but there dangerous because you can't see the beam. Hope this helps a little. Nothing wrong with your lasers it's just the way the different wave lengths burn., edit----- Hey, enjoy your Sanwu's their great units!

405nm is typically absorbed better than other visible wavelengths. It can also be focused to a smaller spot than the other visible wavelengths - combine that with the better beam specs you get with 405nm diodes and you get an all round better burner.

808nm doesn't burn any better than red in my experience for a given power, but it's often available in higher powers.
 

CurtisOliver

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Diachi has got it. Wavelength and beam specs. The 405 is single mode where as the 635 is multimode. The 405 can be collimated and focused better than the 635. A BDR-209 can burn just as well as a M140 IICR.
 

steve001

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Hi guys, today I received three lasers from Sanwu, two of which were a 800mw 635nm Challenger and the there was a 250mw 405nm. The red laser is not very good at burning, albeit bright. The 405 lights things on fire and smokes things very fast when focused, but the red laser is slower even though it's over three times as powerful. Is there an explanation? I've fully charged the batteries. :thanks: :undecided:
There is an explanation; it's fundamental to the wavelength. Shorter wavelengths have higher energy to do work.
 

diachi

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There is an explanation; it's fundamental to the wavelength. Shorter wavelengths have higher energy to do work.

Nothing to do with energy, a 200mW 405nm laser will burn better than a 200mW 650nm, it's purely down to beam specs, smaller beam waist and better absorption. The amount of energy emitted by each is equal.
 

steve001

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Nothing to do with energy, a 200mW 405nm laser will burn better than a 200mW 650nm, it's purely down to beam specs, smaller beam waist and better absorption. The amount of energy emitted by each is equal.
I suggest you double check what you think is true. A web search and you'll have an answer pronto.
 
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steve001

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Which part do you think I got wrong?
The part not knowing the shorter the wavelength the more energy a photon has. Google since you don't believe me. The things you said are useful applications. UV which has a shorter wavelength causes sunburn because photons at that wavelength have enough energy to ionized atoms, so to X-RAYS ... 405nm light can't do that.
 
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diachi

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The part not knowing the shorter the wavelength the more energy a photon has. Google since you don't believe me. The things you said are useful applications. UV which has a shorter wavelength causes sunburn because photons at that wavelength have enough energy to ionized atoms, so to X-RAYS ... 405nm light can't do that.

I'm well aware of that, I don't need to Google anything. I didn't say shorter wavelength light didn't have a higher energy, I said that it doesn't have anything to do with burning capability when powers are equal. When powers are equal energy emitted is also equal.

I know what ionizing radiation is and how it works, and I'm well aware that UV (UVB, NOT UVA) causes sunburn by damaging our DNA, resulting in a repair response which is evident as sunburn.

I suggest YOU do some Googling or reading comprehension practice before trying to correct me.
 
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steve001

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I'm well aware of that, I don't need to Google anything. I didn't say shorter wavelength light didn't have a higher energy, I said that it doesn't have anything to do with burning capability when powers are equal. When powers are equal energy emitted is also equal.

I know what ionizing radiation is and how it works, and I'm well aware that UV (UVB, NOT UVA) causes sunburn by damaging our DNA, resulting in a repair response which is evident as sunburn.

I suggest YOU do some Googling or reading comprehension practice before trying to correct me.
The question the op asked is why does 405nm light burn better than 650nm light and I said fundamentally it's because 405nm light has more energy. Fundamentally is the qualifying word. Look at it this way. Time in a tanning salon under multi direction lamps will give a burn. That same amount under 650nm light won't cause a burn. Why does one cause a burn and the other dies not? It's all about energy of the photons
 

diachi

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The question the op asked is why does 405nm light burn better than 650nm light and I said fundamentally it's because 405nm light has more energy. Fundamentally is the qualifying word. Look at it this way. Time in a tanning salon under multi direction lamps will give a burn. That same amount under 650nm light won't cause a burn. Why does one cause a burn and the other dies not? It's all about energy of the photons


Tanning under tanning lamps can result in a burn because they are emitting IONIZING radiation. 405nm is NON-Ionizing so that isn't an effect. Sunburns are a result of DNA damage from ionizing radiation (UVB), unlike burning something with a 405nm laser which is a purely thermal effect.

The energy difference between 405nm and 650nm photons DOES NOT MATTER. A 200mW 405nm laser is releasing exactly the same amount of energy as a 200mW 650nm laser.

:horse:
 
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CurtisOliver

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The only thing the wavelength is necessary for is matching the absorption bands of the material. The photonic energy is only important for the photoelectric effect and ionisation. That is not what is going on here. Two 10J photon hitting an object will deliver the same 'power' as four 5J photons. The beams specs are the most important. Next power, and then wavelength. What a shorter wavelength does allow however, is a tighter focus meaning a higher power density. This is why high energy gamma rays have been theorised to be able to create a black hole. Put enough energy in a small space. This is the only other scenario where photon energy matters. The incredible energy of the photon with the very tight focus due to its wavelength allows for a collapse of space-time. We are not going to be creating black holes in cardboard any time soon so is irrelevant to your reasoning.
 
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Crazlaser

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The question the op asked is why does 405nm light burn better than 650nm light and I said fundamentally it's because 405nm light has more energy. Fundamentally is the qualifying word. Look at it this way. Time in a tanning salon under multi direction lamps will give a burn. That same amount under 650nm light won't cause a burn. Why does one cause a burn and the other dies not? It's all about energy of the photons
First off, that's not what I asked. I asked why 405nm burns better than 635nm.
Second, are UVB diodes available? Or something like 255nm? I don't know where UVA ends and UVB starts but just curious.
 




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