Is it possible to build a laser from a light bulb?

In summary, the conversation discusses a drawing depicting a generic bulb covered by a mirrored hollow ball with a small hole in the center. It is suggested that the complete light from the bulb will go through this small hole and be bundled by a lens to a distant focal point. However, it is noted that this may be difficult to achieve and the resulting light would not be like a laser. It is also mentioned that most of the light would bounce around and get absorbed, making it not feasible. The idea of using a parabolic mirror and converging lens is proposed, but it is ultimately concluded that it would require a lot of energy and not work as a laser due to the differences in frequency and phase between a light bulb and a laser.
  • #1
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In my drawing you can see:
A generic bulb covered by a mirrored hollow ball.
The hollow ball has a small hole (1 mm diameter).
So the complete light will go through this small hole.
The lens will bundle the light in a very distant (100 km) focal point.

I guess it might be hard to create such a lens. But I don't know.
Is this possible? IMG_1032.JPG
 
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  • #2
The resultant light would not be anything like a laser (I suggest you look up how they work and what they produce), it would be a diffuse glow, not a collimated beam.
 
  • #3
somega said:
So the complete light will go through this small hole.
No it won’t. Most of it will bounce around and eventually get absorbed, heating up the enclosure.

Laser light is coherent. Light from an incandescent bulb is not.
 
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  • #4
When I was a kid I tried to make a planetarium star projector by making numerous tiny holes in a piece of aluminum foil that I then draped around a 100W light bulb. I didn't get a star pattern on the ceiling. And it didn't take long for the bulb to melt.
 
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  • #5
somega said:
So the complete light will go through this small hole.
If you want to do this, I think you have to make a parabolic mirror with a converging lens in the focus.

Nevertheless, you just will take a lot of energy and it won't work as a laser.
The converging lens will give you a point where all beams come together, while the laser is a punctual emission that just goes straight ahead, with all beams parallels (so you can consider it as a single beam).
lenses-sections-forms-Refraction-light-f-length.jpg

More info:
The laser emits light only in one frequency (thus the monochromatic light) while the light bulb emits in all frequencies (white light). Besides, every wave in the light bulb has a phase shift respect to the others, in the laser all waves are in phase.
 

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