High power lasers and nature of light waves

[thalion777]

I am trying to learn about high-powered lasers. i am wondering what effects the actual power of the laser (the part that makes it burn). is it wave-length or frequency. Is gamma rays more destructive then visable light, ect. Any help would be greatly appreciated

 

[chrisbaird]

Higher frequency beams carry more energy (E = hf). In order of lowest frequency to highest, and therefore least destructive to most, we have: radio waves, terahertz, infrared, visible light, ultraviolet, x-rays, gamma rays. That is why x-rays can give you cancer but infrared does not. In free space, wavelength and frequency are trivially related, f = c/lambda, so that higher frequencies are always shorter wavelengths. You only need to talk about one and other is understood.

That being said, the ability of a laser to damage an object depends on many things: the intensity of the laser beam, the spot size to which the beam is focused, and the way in which the specific material responds to the beam (which is frequency dependent).

 

[thalion777]

Higher frequency beams carry more energy (E = hf). In order of lowest frequency to highest, and therefore least destructive to most, we have: radio waves, terahertz, infrared, visible light, ultraviolet, x-rays, gamma rays. That is why x-rays can give you cancer but infrared does not. In free space, wavelength and frequency are trivially related, f = c/lambda, so that higher frequencies are always shorter wavelengths. You only need to talk about one and other is understood.

That being said, the ability of a laser to damage an object depends on many things: the intensity of the laser beam, the spot size to which the beam is focused, and the way in which the specific material responds to the beam (which is frequency dependent).

if you got placks constant (H) and multiplied it with the frequency (F) you get E. How do you know what the frequency is if you know what type of wave it is. For example, you have a gamma, or y ray, which is between the frequency of about 10^20 to about 10^24 which is measured in "V", i believe. What is "V" and how is it measured, and when you multiply that tiny number of Plancks constant with that number, you get a number that represents energy. What is the energy measured in and how does that relate to in the real world?

 

[thalion777]

also, what relates more to power of laser, wavelength or frequency. According to wikipedia, they are like opposites. y waves are the highest frequency and lowest wave length and vice-versa

 

[thalion777]

basically, I am trying to learn how to make the most powerful laser at the smallest size, although energy is nearly infinite. I want it to be like the industrial lasers which are c02. it doesn't have to be visable light, infact, i would prefer it wasnt

 

[chrisbaird]

Frequency is measured in cycles per second (1/s), also labeled Herz (Hz). For instance, a 2 THz laser means 2 TeraHerz or 2x10^12 cycles per second. Like I said, in free space, frequency and wavelength are trivially related, so it does not matter which one you use in your equations. I suggest you work through an introductory physics textbook because designing lasers involves much more difficult concepts than understanding the relationship between frequency and wavelength.

 

[thalion777]

[URL]http://upload.wikimedia.org/wikipedia/commons/f/f1/EM_spectrum.svg[/URL]
that doesn't seem possible considering that frequency and wavelength are totally different. from 10^24 to 10^-16. also, would a high school physics textbook work? i am not even in chemistry as i am a sophomore in high school. i am trying to get ahead in science as i have a knack and an interest in physics and inventing and have always been at the head of my class

 

[lewando]

that doesn't seem possible considering that frequency and wavelength are totally different.

What does not seem possible? That frequency and wavelength are "trivially related"? They are. You should soon understand that.

also, would a high school physics textbook work?

I am not sure about your plans. I have seen some HS textbooks and they typically do not discuss design of laser systems. So, assuming you are looking at some advanced concepts, you should have in your possession a college textbook just to get a peek at what lies ahead. And to see if you are able to deal with the math. And please do online research.

i am not even in chemistry as i am a sophomore in high school. i am trying to get ahead in science as i have a knack and an interest in physics and inventing and have always been at the head of my class

That is awesome. Don't be discouraged, but be realistic. And be patient. There is always a lot to learn which takes time.

 

[Delphi51]

The E = hf formula gives you the energy of one photon in the beam of light. Frequency and wavelength for any wave are related by V=f*λ where V is the speed of the wave (m/s), λ is wavelength (meters).

The really fascinating thing about light is that it has both wave and particle properties that show up in different experiments. In high school physics you should see interference (shows that light is a wave) and the photo electric effect (where light acts as particles - photons).

High school physics is fairly advanced. In fact, you will not see much in first year physics at university that is not in high school physics, though the problems will be more complicated and you may use more advanced math (calculus). Definitely read the high school physics books. Look up stuff in Wikipedia.