Fiber Lasers

Mad hatter syndrome?

I don't think that would be an issue.

Mercury is handled safely in lots of industrial applications,such a flourescent lighting,etc.

Why not just use water?

The volumetric specific heat capacity of water is more than double that of mercury.

As I understood the problem, the heat was created by the reflection of the photons from the reflective layer on the fiber.

Replace this layer with mercury,is what I intended to ask.

I know there are fluids with a higher specific heat than mercury,but are they reflective,like a mirror?

A tube filled with mercury with the fiber in the center of the tube.

The mercury could be circulated to a heat exchanger to dissipate the heat.

Well you could use silver....this is used to coat the backs of rhinestones and mirrors...then coated with enamel...

Silver is too slow--it's gotta be quicksilver....

The purpose in using mercury is to have a circulating reflective medium that could reflect at the same time it was removing heat.

Why do you need the fiber at all?

We all need fiber! It helps keep us regular.

Too early, Eagle, too early.

Fiber optics really do not require a "coating" to operate. The problem is that no matter how pure they get the quartz for the fiber, there is still some residual light absorption by the fiber itself, and the light absorbed gets converted into the normal modes of vibration, etc, resulting in phonon excitation of the local crystallite zones, which in effect is heat (momentum), and this results in failure of the optic. There are layers within the fiber itself, one may be pure quartz, then another may be a form of glass, and all "layers" have a distinct index of refraction. Any non-collimation of the transverse excitation mode of the laser beam is reflected by critical angle reflection at phase boundaries. The problem extant is small, but finite optical absorbance of light emitted.

Fibber optics, on the other hand, only require a certain waving of the hands to operate.

Found this....

http://www.coractive.com/pdf/publications/ThermalEffectsInHighPowerCWLasers_SPIE2009.pdf

Fiber lasers are used as light amplifiers, not as generators of coherent light , so they don't have reflective mirrors. See "erbium doped fiber amplifiers"

The center core of the fiber is doped,the outer part of the fiber is not doped.As the input laser is reflected off of the lining,it passes through the doped center core,creating the amplified laser.

http://www.scientificamerican.com/article/laser-weapons-get-real/?WT.mc_id=SA_TECH_20150602

Laser light is steered down the fiber by one of two methods: total internal reflection, or refraction due, to the core having a higher refractive index than the cladding. Both of these processes are 100% efficient. Reflection from a metal surface is not perfectly efficient and multiple reflections would reduce the gain.

The refractive index of the fiber increases as you get closer to the surface of the fiber. This is how the light is bent back into the fiber.

If they are amplifying the light, they are "generating" more light than what was incident, this is what is known as optical gain.

Oh, heck. Let's see... First Mercury is poisonous, it has a very high surface tension, which might make it very hard to get it into the fiber's cladding, the mercury would distort and mess with inter-cable reflections.

Also, I'm sure that there are far better thermally conducting materials out there.

Iz just sayin'.

My understanding is that the retention of light within the fibre is due to total internal reflection, itself a function of the high refractive index of the glass in relation to its surround. Adding an external reflective coating would not achieve anything further.

I guess you will have an immense problem:

Using mercury, unless vaporized as a coating will not work. You can not even flatten it out - try to break a mercury thermometer and see what happens with the liquid.

I have assembled tons of neon and other fluorescent applications and the liquid mercury serves an other purpose there.

It may be illegal. You'd have to check local, state, national, and international (RoHS) standards and regulations. Mercury in fluorescent lamps is one of the few RoHS exemptions for Mercury.

Thanks to the feedback and comments from all who responded,I have learned a lot about fiber lasers.

The most heat is not generated within the fiber,but in the Bragg Filter,and my idea of a reflective inner coating would create a second surface reflector,as pointed out, that would create noise,even it it were possible to implement the idea as proposed.

I have been put on the right track,and will dig deeper into the subject.

Thanks everyone!