Concentrating radiation from blackbody with lens

In summary, the conversation discusses the use of lenses to concentrate infrared radiation from a blackbody for imaging and energy transfer purposes. It is possible to use infrared lenses, but they must be made of a material that is not opaque in the infrared. For long-term energy transfer, mirrors may be more suitable for beam shaping. The temperature of the lens or mirror must be different from the heat source in order to avoid interference from their own blackbody radiation.
  • #1
Stanley514
411
2
1)Is it possible to concentrate infrared radiation from a blackbody with a lens?
2)Should a lens be at different temperature from a blackbody?
 
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  • #2
Sorry, misunderstood the question!
 
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  • #3
1) Yes. You can buy nowadays infrared cameras with infrared lenses. See http://www.flir.com/thermography/americas/us/products/?id=17972", for example. Infrared radiation is an electromagnetic wave just like visible light, so it obeys the law of refraction just as well and bends through a lens. The trick is to build a lens out of a material is not opaque in the infrared.

2) A passive lens needs to be at a lower temperature then the blackbody, otherwise the lens' own blackbody radiation will swamp out the signal. But this is automatic for typical applications. The temperature of living creatures, machines in use, etc. tend to be higher than the room temperature at which the unmodified lens exists. To image lower temperatures than room temperature, two methods can be used. The camera can be cooled. This can be expensive but effective, as the http://en.wikipedia.org/wiki/Cosmic_Background_Explorer" mission demonstrated. Or the camera can be actively stabilized but not significantly cooled. Using this approach, the system is held at a temperature and differences in temperature are measured.
 
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  • #4
I thought on possibility to use a lens method in geothermal power harness.
For exampe underground cavity could be properly shaped and filled with water or similar liquid to concentrate infrared light coming from underground and direct IR ray to the surface where it could be transformed to electricity with help of photocells.I think it could eliminate problem with water cycling and management.But as you said the lens should stay at different temperature from heat source than it makes some complications.
I thought on possibility to reduce amount of holes to cycle water and increase heat harvesting from large underground areas with minimal amount of holes to drill.Unfortunately water is not very energy dense carrier and it requires lot of expensive drilling.
 
  • #5
Ah, you don't seem to mean for imaging purposes, but for long-term energy transfer purposes. In that case, I think mirrors would be more suitable than lenses for beam shaping.
 
  • #6
chrisbaird said:
Ah, you don't seem to mean for imaging purposes, but for long-term energy transfer purposes. In that case, I think mirrors would be more suitable than lenses for beam shaping.

This is why it helps to give context when asking questions.

Claude.
 
  • #7
Ah, you don't seem to mean for imaging purposes, but for long-term energy transfer purposes. In that case, I think mirrors would be more suitable than lenses for beam shaping.
Do you think something similar to what I was thinking about could be practically created?With help of mirrors?Should thouse mirrors stay at different temperature from underground cavity?
 

FAQ: Concentrating radiation from blackbody with lens

How does a lens concentrate radiation from a blackbody?

A lens is able to concentrate radiation from a blackbody by refracting, or bending, the light rays that pass through it. This refraction causes the rays to converge at a single point, increasing the intensity of the radiation at that point.

What is a blackbody and why is it used in this context?

A blackbody is an idealized object that absorbs all radiation that falls on it. In this context, a blackbody is used because it radiates energy at all wavelengths according to its temperature, making it an ideal source for studying the properties of radiation.

How does the shape of a lens affect its ability to concentrate radiation?

The shape of a lens can greatly affect its ability to concentrate radiation. Lenses with a larger curvature, such as convex lenses, are able to bend the light rays more and therefore concentrate the radiation to a greater degree. Additionally, the size and placement of the lens in relation to the blackbody can also affect its concentration abilities.

Can a lens concentrate all wavelengths of radiation equally?

No, a lens is not able to concentrate all wavelengths of radiation equally. This is due to the phenomenon of chromatic aberration, where different wavelengths of light are refracted at slightly different angles. This results in a slight separation of the wavelengths and can affect the concentration of radiation.

What are some practical applications of concentrating radiation from a blackbody with a lens?

There are many potential practical applications of concentrating radiation from a blackbody with a lens. One example is in solar energy collection, where lenses can be used to concentrate sunlight onto a smaller surface area, increasing the efficiency of energy conversion. Another application is in infrared imaging, where lenses can be used to focus thermal radiation emitted by objects to create detailed images for various purposes such as medical imaging or military surveillance.

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