The shorter wavelengths allow the photons to rapidly excite a target area, which leads to faster transfer of energy.
Take a 660 laser and a 405 @ ~300mW:
- The 405 will be able to impart it's energy into the target faster and burn it.
- The 660 will still be able to burn the target but will take a longer amount of time to do so.
True, blue photons do carry more energy, but that also means it's harder to produce them. 200mW is 200mW, be it blue, green, red or microwave. The power is the same. Count of the photons to get that power is not the same.
So simply do not compare colors of lasers, just compare their power. Then the more powerful is well .. more powerful.
"She said that green lasers were more powerful than red, and purple were (more) powerful than green."
I think that the original statement isn't defined properly.
Get a different or better definition for her use of "powerful".
My biggest problem with teachers way back when going to school had to do with the single mindedness of some. They only think of things in their own way and do not allow for possible misinterpretation by others.
I have been told that I am a great teacher as I can always state a point or thought in many different ways allowing for everyone to understand. (I find it to be a good mental exercise personally. Keeps your thought processes limber, so to speak.)
The electrical definition of power is actually quite limited. 500 mw is 500 mw no matter what wavelength.
However, as explained previously here, the energy state of the photons of different wavelengths will differ greatly.
So depending on how the original term "power" was being intended is the real question.
Or was that a paraphrase of a discussion with the wrong terminology being posted by you ?