Is this the simplest optical cloak possible?

In summary, the authors of the "A Simple Unidirectional Optical Invisibility Cloak Made of Water" paper chose a system with four refractions for each light ray to create a cloaked area that is a parallelogram. This was likely done for simplicity and ease of testing. However, it is possible to create a cloak with only three refractions, although it would require more precise design. The paper could benefit from an additional diagram to show the device without the giraffe, as well as more information on the device's ability to work in different planes. The concept of using water as an invisibility cloak is not entirely new, as it has been used by stage magicians for decades.
  • #1
Christofer Br
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https://www.researchgate.net/publication/273269952_A_Simple_Unidirectional_Optical_Invisibility_Cloak_Made_of_Water
Why did the authors of this cloak not choose a system with only three refractions for each light ray, so that the cloaked area would be a parallelogram? Is this impossible, or would it decrease the cloaking angle?
 
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  • #2
You could always write them and ask them, but I suspect the answer was simplicity. It's obvious how to do this with 4, and 4 breaks down to 2+2 so you can test half of it easily. It probably can be done with 3, but not so easily - the middle pice has to be just right: you need to make sure every ray spends an equal time in air and water, and that all the angles work out.
 
  • #3
Page 3 of the paper could use a fourth picture between pictures (1) background only and (2) 14 cm model that shows (2') background with device sans giraffe. Selection of background with hazy patterns and the large central tree figure directly behind the giraffe appear forced; designed to assist the illusion of continuity. The inexpensive nature of the device is intriguing.

Agree with simplicity as the answer to the OP. Minimal configuration that works ( and costs least).
 
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  • #4
I see the diagrams are 2 dimensional. Would it work in all planes? Prob some distortion.
I'm amazed that the idea could be 'new',
 
  • #5
sophiecentaur said:
I'm amazed that the idea could be 'new',

It's been done with reflection for decades (centuries) by stage magicians. As they say "it's all done with mirrors".
 
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Likes Klystron and sophiecentaur

What is an optical cloak?

An optical cloak is a device that can manipulate light waves to make an object appear invisible or appear as something else. It works by bending light around the object, similar to how water distorts the appearance of objects underwater.

How does an optical cloak work?

An optical cloak works by using special materials called metamaterials that can bend light in a specific way. These materials are designed to have unique properties that are not found in nature. When light hits the metamaterial, it is redirected around the object, making it appear invisible or transformed into something else.

Is this the simplest optical cloak possible?

At this point in time, it is difficult to say whether this is the simplest optical cloak possible. Scientists are still researching and developing new types of metamaterials that can manipulate light in different ways. It is possible that in the future, a simpler optical cloak may be created.

What are the potential applications of an optical cloak?

An optical cloak has many potential applications, including military and defense uses, such as making objects invisible to radar or infrared detection. It could also be used in the medical field for creating non-invasive medical imaging devices. Additionally, an optical cloak could have applications in consumer products, such as creating more efficient solar panels.

Are there any limitations or challenges to creating an optical cloak?

There are still many challenges and limitations to creating an optical cloak. One major limitation is the size of the object that can be cloaked. Currently, optical cloaks are only effective on a small scale. Additionally, the materials used to create an optical cloak are often expensive and difficult to manufacture. There are also technical challenges in creating a cloak that can work with multiple types of light waves and from different angles.

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