Connecting lasers

  1. Sep 24, 2011 #1
    Hi, i have question about lasers. What happens when I target same spot with 2 laser beams ? Lets saw two 1W laser. Will be final effect equal to one 2W laser ? Thanks
  2. jcsd
  3. Sep 24, 2011 #2


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    The light from the two lasers would not be coherent with each other, so its not exactly the same as using one stronger laser.

    But I guess the incident light intensity would be double.
  4. Sep 24, 2011 #3
    You get 2 watts and nothing interesting unless you make a special effort to arrange the spots so that the two beams come from essentially identical lasers along essentially identical paths as in an interferometer. Then you'd begin to see fringes in the spot, probably mostly tilt and focus, so the intensity within the spot can vary up to 0 to 4 watts locally.
  5. Sep 24, 2011 #4
    Why are you interesting in this?
  6. Sep 24, 2011 #5
    So making 2W laser is better... Can you please recommend me type of laser ? I wanted to build 2x1W with laser diodes, but 2W diode is quite expensive. isnt hene or co2 cheaper at that power ?
  7. Sep 24, 2011 #6
    You can buy 100 diode lasers(5mW each)and make an array. If you will be able to phased them... you will receive 2x100x5mw = 1W of power. However you will have to make good cooling system for continuous laser.

    I advise you to buy YAG:Nd+3 glass(, two very good mirrors and few blue diodes.
  8. Sep 24, 2011 #7
  9. Sep 24, 2011 #8
    well those 5mw would cost much more than one 1w(and i am not speaking about synchronization...) That Nd:YAG looks interesting, but I hardly think that I can find 1w YAG below 20$...
  10. Sep 24, 2011 #9
    You can buy cheap one then disassemble it. After it, You can use YAG glass as active region and with proper cooling and pumping you will be able to increase output power.
  11. Sep 25, 2011 #10
    @platis: I've been just googling for several hours but I still dont understand what you meant. I see you have masters at laser sience, but I am just high school student. Can you please explain me in little more detail ? Where can I get so cheap YAG laser? What is that YAG glass atc.... I still think that laser diode is probably the best solution for me(easy to build and also cheap)
  12. Sep 25, 2011 #11
    @martin1512: mmm. You will no be able to create 1W laser at home without proper education. Also, Laser with 1W of output power is VERY!! dangerous for eyes. I do not recommend you to do such experiments at home without proper defense. Sorry, due to yours safety I will not help you.

    From Wiki

    Class 3B

    A Class 3B laser is hazardous if the eye is exposed directly, but diffuse reflections such as from paper or other matte surfaces are not harmful. Continuous lasers in the wavelength range from 315 nm to far infrared are limited to 0.5 W. For pulsed lasers between 400 and 700 nm, the limit is 30 mW. Other limits apply to other wavelengths and to ultrashort pulsed lasers. Protective eyewear is typically required where direct viewing of a class 3B laser beam may occur. Class-3B lasers must be equipped with a key switch and a safety interlock.


    Class 4 lasers include all lasers with beam power greater than class 3B. By definition, a class-4 laser can burn the skin, in addition to potentially devastating and permanent eye damage as a result of direct or diffuse beam viewing. These lasers may ignite combustible materials, and thus may represent a fire risk. Class 4 lasers must be equipped with a key switch and a safety interlock. Most industrial, scientific, military, and medical lasers are in this category.
  13. Sep 25, 2011 #12
    @plantis : maybe you're right that 1W laser is quite tough for the beginning. But I think my electronical skills are good enough(I've done several projects so far) so I was only curious about the optics part(maybe i'll buy book). To the safety, I was alredy familiar with the article you posted and I'm aware of all risks and dangers that come with laser device :).
  14. Sep 25, 2011 #13
    Laser on YAG Nd+3 does not have a lot with electronics. It will be totally optics project. You will only need some power supply unit. Everything else will be in optics - lenses, active region, optical pumping and so on.

    You will have great troubles to make your laser generate laser light.
  15. Sep 25, 2011 #14
    Ok you convinced me, I'll go with laser diode. YAG may be next one :O
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