Absorbing and reflecting light

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Discussion Overview

The discussion revolves around the concept of materials that can absorb light from one side and reflect it on the other. Participants explore theoretical and practical aspects of such materials, including their existence and potential applications in projects like waveguides and solar ovens.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants question whether a material can exist that absorbs all light on one side and reflects all light on the other, with one suggesting that such a contraption does not exist.
  • One participant mentions that transparent substances also interact with light, implying they may absorb and reflect in different contexts.
  • Another participant discusses the concept of one-way mirrors and how they operate under specific lighting conditions.
  • The event horizon of a black hole is proposed as a potential example, though it is later clarified that it does not function as a physical object that absorbs or reflects light.
  • A black-painted mirror is suggested as a practical example that reflects light from one side while absorbing it from the other.
  • One participant expresses a desire to create a waveguide that absorbs light from outside and reflects it internally, seeking clarification on the terminology used.
  • There is a discussion about the feasibility of achieving the desired effect without violating thermodynamic principles, with suggestions of using mirrors to concentrate light instead.
  • Participants express interest in cost-effective methods to achieve the desired light manipulation for practical applications.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the existence of materials that can absorb light from one side and reflect it on the other. Multiple competing views are presented, with some arguing against the possibility while others suggest alternative approaches.

Contextual Notes

There are unresolved assumptions regarding the definitions of absorption and reflection, as well as the implications of thermodynamic laws on the proposed materials. The discussion also lacks clarity on the specific applications and constraints of the proposed concepts.

fouad89
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Is there anything that absorbs light from one side and reflects it on the other?
 
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fouad89 said:
Is there anything that absorbs light from one side and reflects it on the other?

Virtually every common surface both absorbs and reflects light. Did you mean something that absorbs ALL light on one side and reflects ALL light on the other? If so, I do not believe that any such contraption exists. Prove me wrong, someone!
 
whatelse do you think transperent substances do ??
 
I read that you can trap light in a box using one way mirrors, but I read the way one way mirrors work is that one side must be dark (the clear and transparent side) and the lighting on the other side must be normal (the mirror side)
 
The event horizon of a black hole?
 
A mirror painted black on its back will strongly reflect light incident on its front surface and strongly absorb light incident on its back surface. Do you have something http://www.scientificsonline.com/solar-radiometer.html" in mind?
 
Last edited by a moderator:
This is interesting but it is not what I had in mind. I am trying to make a wave guid, by absorbing light from outside and then having the light bounce around inside my project.
 
"Absorbing" may not be the proper term for what you want. It seems that you want the wall to be transparent for light coming from outside and reflective for light coming from inside the guide.
If the light is absorbed by the wall you'll have no light going inside the guide. It will just heat up the wall.
 
Yes this is what I want, does this exsist ?
 
  • #10
Or even how can I make it
 
  • #12
MikeyW said:
The event horizon of a black hole?

No, the event horizon is merely a boundary around a black hole where the gravitiational pull becomes strong enough to trap light. It is not a physical object. It also doesn't absorb or reflect light.
 
  • #13
There's nothing that is reflective on one side and transmissive on the other side. Such a material would violate the second law of thermodynamics. But there may be other ways to achieve what you are trying to do, maybe by concentrating light with mirrors. Are you building a solar oven or something?
 
  • #14
Khashishi said:
There's nothing that is reflective on one side and transmissive on the other side. Such a material would violate the second law of thermodynamics. But there may be other ways to achieve what you are trying to do, maybe by concentrating light with mirrors. Are you building a solar oven or something?

Kinda in a way. But how can this be achieved while maintaining a cost efficient standard? Any recommendation or suggestion is helpful.
 

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