Lasers and Color light

You people gave me info about red and blue lasers. Does anyone else have any information about other colored lasers in the visible spectrum?

Thomas, can you give me information about other colored lasers?

If no one here knows anything about other colored lassers in the visible spectrum, who should I ask?

There are green lasers available, with an emission wavelength of 532 nm, but I'm not sure how common they are compared to red and blue.
See, for example, Green Lasers. For more information you could try getting in touch with technical service at an optics company such as Edmund Industrial Optics (www.edmundoptics.com) or Ocean Optics (www.oceanoptics.com).

I know that red and blue diode lasers are used for massage therapy.

Perhaps you might start by paying attention to the information you were already given. If you follow the link in raprap's July 1 post, you will find that it links to a page on the exciton website that lists a cornucopia of lasers throughout the UV, visible, and IR spectrum. You can then find out more about the power they emit by googling for these types of lasers. If it's the energy per photon you are interested in, you can calculate it using the following equation and definitions.

E = h * c/lambda, where h = Planck's constant = 6.626176 * 10^(-34) J·s c = speed of light in vacuum = 2.99792 * 10^8 m/s lambda = wavelength of the light emitted by the laser.

Hope that helped.

all very good replies to your question....may i just be direct to your questions.

by varying the colour of your laser....lets assume that the power output of each colour is the same. well then, 10 watts of power is 10watts, so the power output is the same and so there is no difference in changing the colour alone.
however, if the material you are aiming at has the property to absorb more red than it does blue, then your 10watts of energy is going to have more effect. so in this sense, your colour change has a relative meaning.
this also takes care of your light colour being more cooler with a different colour. its all down to the absorption of the material.

do not equate being cooler with the speed of the lasers light.
the speed of the light is a constant and this constant only changes in a medium. the reason for this change is due to the properties of its wavelength.
some understanding must be had here first before it makes sense.
when light enters the surface of a medium, it ceases to be the photon that we know. it is absorbed as a unit of energy and is transmitted along the material, or through it, as an electron shock or vibration. this energy is then recomposed at the other surface and the energy once again appears as a photon. typically, these electron vibrations are known as phonons.
however, electrons cannot transmit its energy at the speed of light as this would break the physical laws as we know it and so the speed is determined by the amount of initial energy.
blue light will travel that much faster than red. i believe that chromatic abberation in lenses is an example of this. someone correct me if im wrong.


your final question is suitably entangled with your original ones.
as properly explained, black light is ultra voilet radiation or light....this range is just above blue light. its energy is higher than blue light.
the same rules of absorption applies to it.
all materials have their own spectral widths or energy bands at which they can either vibrate or be stiff to a particular range of energy.
this quality determines what effect any given light is going to have on them.
so, whereas visible light will readily pass through glass, infra-red may not. and where quartz is not a good transmitter of light, it is for infra red.
hence, we can make a material for any given sets of wavelengths to act like filters like we do with our cameras.

in medicine, ultra violet is used to treat certain skin complaints like psoriais as the depth of the skin complaint is equivalent with the penetrating depth of the chosen uv wavelengths.
varicose veins and other similar skin defects are treated with wavelengths of the order of 576nm...well above the typical uv wvelengths of 300 to 400nm.
hopefully this is an example of the effectiveness of its change in colour and will be a suitable answer to your question.

now i will examine your second quandry...that of the range of lasers...

you can get a laser of any colour and the means of generating laser light are growing in numbers everyday.
for example....
there are...
dye laser....a dye of of a particular colour is excited to produce the light.
crystal laser.....these crystals have unique colours and hence produces those very same colours...
diode laser...these are made from semiconductors like leds but the light is more coherent...coherent light is light packets that are all travelling in the same direction and are in phase with each other...
gas laser...the gas is exited to produce its own radiation at its characteristic frequency or wavelength.

a new breed of lasers are the electron lasers. these are tunable over a variety of wavelengths are currenty found in research labs. the fermi lab is currently building a very good one which is tunable over a wide range of energies.
it is hoped that these lasers will be rapidly put into production for their use in medicine. this will prevent having different laser for differen types of treatment. an all in one solution if you like.

there is no special advantage of one laser over the other. each laser serves its own purpose well and it would be silly to say that this one is better than that one.

the medical field uses the widest range of colours and types in laser
technology and is problably only outdone by laser labs doing research.

Thank you. What I meant to ask was:
Do different colered lasers serve different functions?

yes...just as i have outlined above and why they do, especially in medicine.
however, to expand briefly, some lasers are better than others at producing bigger powers....so they may be chosen for that particular task.....though it may seem to be a colour thing, it isnt really by choice of colour but more to do with how easily manufactured it is and how easy the agents (dye or crystal) are available and their costs etc that become the deciding factors.

How do diode lasers and crystal lasers work?

oooo....been away for a while....

tough question....not enough space but basically....

the harder one is the diode laser in that its a semiconducter material and it will have impurities grown on a very thin layer.
by sticking a vltage across this lauer between p and n junctions, we can exite the doped layer to produce a characteristic wavelength of light dependent on the dopant used.
this occurs when the electrons have to jump the gate and in doing so, create a gap which gets filled by other electrons coming in.
in filling these gaps, they surrender the excess kinetic energy as a photon. look up e=mv(sq)....its typically that behaviour but on the electron scale. some will talk about tunnelling and such but its best to view it like that for simplicity.

dye lasers are slightly different in that mirrors are used, similar for gas and crystals.
these mirrors are arranged to face each other with the dye medium in between.
you basiclly either exite the medium using a high volatge or a flash lamp(very bright one) and get some light going between the mirrors.
the electrons in the material are exited on their characteristic energy levels and will produce photons akin to that level....these join the rest of light bouncing and will further exite other electrons on similar electron levels.....its basically a cascade effect from the original energy pump but with the difference that the final light will all be in phase with each other as they exit one particular mirror that is acting like a shutter.
you then get a burst of laser light.
because all the light is in phase, its collective more powerful. such light when hitting a surface will tend to heat a surface more efficiently than light which rent in phase.
hence the use and purpose of lasers.

hope this helps.