Conservation of Energy Problem

[PiersNewberry]

There is an interesting article here

http://focus.aps.org/story/v18/st4

about a method for tunnelling light through usually opaque materials. Half way through they mention that one light ray becomes two:

"When a light ray passing from glass into air strikes the interface at a sufficiently shallow angle, it reflects entirely back into the glass with no transmission into the air. In this effect, known as total internal reflection, some of the electromagnetic field strays across the boundary between the two materials as a so-called evanescent wave, which carries no energy away. But if the evanescent wave encounters another block of glass a short distance away, a true light wave with reduced intensity appears in the second block."

I am interested to know where the extra energy for the second light wave comes from, and is this a good way of building a power station, cycling the energy through the system and getting apparently more out each time.

 

[geo_alchemist]

I am not a physicist; not even close to it. so excuse me if I am telling stupid thing but right the next paragraph says that:
"This optical phenomenon is mathematically identical to the quantum tunneling of a particle through a classically insurmountable barrier."
If my logic does not betray me, the energy comes from the similar source as for the particle tunneling through the barrier.
The text you copied above, does not mention if the internal reflection is still total if the mentioned evanescent wave encounters another block of glass.

 

[astrokreng]

I find this article on tunnelling light through opaque materials to be fascinating. The phenomenon of total internal reflection, where a light ray reflects back into a material with no transmission into the surrounding medium, has long been studied and utilized in various applications. However, the concept of creating a second light wave from the evanescent wave produced by this reflection is a new and intriguing development.

To address the question of where the extra energy for the second light wave comes from, we must consider the law of conservation of energy. This principle states that energy cannot be created or destroyed, but can only be transformed from one form to another. In this case, the energy for the second light wave is not coming from nowhere, but rather from the original light ray that was reflected back into the material. As the evanescent wave travels along the boundary between the two materials, it is able to interact with the second block of glass and transfer some of its energy to create a new light wave. Therefore, the total amount of energy remains constant, but is distributed between the two light waves.

While this may seem like a potential source of unlimited energy, it is important to note that the intensity of the second light wave is reduced compared to the original light ray. This means that the total amount of energy that can be extracted from this system is limited. Additionally, the process of creating the second light wave requires precise conditions and materials, making it impractical for use in a power station at this time.

In conclusion, the concept of tunnelling light through opaque materials and creating a second light wave is a fascinating development in the field of optics. However, it is important to remember the principle of conservation of energy and the limitations of this phenomenon in terms of practical applications.