laser diode help red vs blue

i am making a laser and i did some research. i read som website that said as you go from lower frequencies to higher frequencies there is more energy in the wave, would that mean that a blue laser diode would be more powerful than the red laser diode when ur burning something?

Yes, but that is also combined with a host of other factors that make it not really that simple.. Burning power is dependent on several outside influences and is not the best way to describe the power of a laser. Factors such as the color of the object being burned, wavelength of the laser, focus, etc.. all play into "burning power"..

ElektroFreak said:

Yes, but that is also combined with a host of other factors that make it not really that simple.. Burning power is dependent on several outside influences and is not the best way to describe the power of a laser. Factors such as the color of the object being burned, wavelength of the laser, focus, etc.. all play into "burning power"..

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The objects resistance to wavelength X (ex: human skin has a high resistance to IR and a lower resistance to UV)

What you need to really look at is which color appeals to you more. Each can be equally powerful (405nm cost more per mW). If red is your thing go red. If near invisible 405nm is what you like, go that direction. Hell.. build both. :beer::beer:

Not threadjacking, just adding to the list

-Mike

well i already ordered both online so i will conduct an experiment
they will be at the same distance, ill use som black rubber, try th get them at the same focus err watever, same power,same room temp,etc:yh:

Power is power. 100mW of blue/violet light is EXACTLY the same power as 100mW of red light. How that light is absorbed into a material depends on the material, and that will affect burning, but power is power, 100mW is 100mW.

What you read is true, a single photon of blue/violet has more energy than a single photon of red. So if a 100mW violet beam is the same power as a 100mW red beam, then it is clear there must be fewer violet photons "in" the violet beam than red photons "in" the red beam. Each violet photon has more energy than a red photon, so you need fewer violet photons to have the same power in a laser beam. But the power of a laser is the total of all photons, so 100mW is 100mW, no matter what the color is, so the burning ability is exactly equal for both colors.

If your target absorbs colors differently, then burning ability will be different, but not directly because of what you're talking about (absorption is related to photon energy, but in a more convoluted manner than is worth discussing here).

In practice however, common substances will absorb the violet much better than the red. With my PHR at about 90-100mW (120mA), it slightly stings the skin after a few seconds exposure when focused to infinity (even in a couple meters distance). The 250mW red (LPC at 420mA) on the other hand is completely unnoticeable under similar conditions. I have to focus it down quite a bit to give the same sensation (actually the hairs on my arm start smoking first...)

would a violet/blue laser be able to burn brighter color things (yellow,pink,white colored things)or would i still have to mark it with a black sharpie?

You can cut white paper with a Blu-ray, I have never managed that with a red.

Regards rog8811

this is like saying if a pound of air is heavier than a pound of iron, 1mW of blue is the same than 1mW of red or bluray, ofc there are less photons per mW on the bluray.

oh i understand now thanks

so what you guys are saying is a red will always need black marked stuf to burn?

dr-ebert said:

In practice however, common substances will absorb the violet much better than the red. With my PHR at about 90-100mW (120mA), it slightly stings the skin after a few seconds exposure when focused to infinity (even in a couple meters distance). The 250mW red (LPC at 420mA) on the other hand is completely unnoticeable under similar conditions. I have to focus it down quite a bit to give the same sensation (actually the hairs on my arm start smoking first...)

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Really? Because I have focused down my 250mw LPC to about 5 feet away onto my friends leg.. He freaked out after about 4 seconds. Maybe because his skin is a darker complexion?

Well that's what I said - IF you focus it, then you feel it. There will be a maximum distance for that, because the minimum possible dot size increases with distance due to divergence. And sure, the darker your skin, the more you feel it!

I tried burning myself & did not feel anything at 6 in away I put a black dot with marker & bam it burned me. New tool for surgery! Skin tags, moles ect be gone!