Why can photonic crystals be used to create a super lens?

[zhillyz]

Firstly, sorry if this doesn't go here please feel free to move it as I was a little confused where to put it.

TL:DR Doing a project question interests me, "Why can photonic crystals be used to create a super lens?"

Okay so I am doing an undergraduate project for my honours year that I find very interesting it is theoretical maths based project. Assuming a one dimensional binary or ternary photonic crystal that has periodic dielectric layers with no charge or current, you get omnidirectional "band gaps" where the crystal transmits(or refracts) nothing and reflects everything, so this can be used as an application anywhere that needs light manipulation. I am doing this for one dimensional photonic crystals but you can create 2D and 3D ones as well.

I was looking into applications though and came across a "Super Lens" where using PC you can see the near field wave and therefore a lot more detail than what we are limited to by the wave length of light and the far field.

Can anyone explain how this application would be done?

Thank you.

 

[eljose79]

Thank you for sharing your project question with us. I am a scientist with expertise in photonic crystals and I would be happy to provide some insights on how they can be used to create a super lens.

Firstly, let me start by explaining what a photonic crystal is. A photonic crystal is a material that has a periodic variation in its refractive index, similar to a crystal lattice in a solid material. This periodicity creates "band gaps" where certain wavelengths of light cannot pass through the crystal, while others can. This is what you mentioned in your post as the crystal transmitting or refracting nothing and reflecting everything.

Now, to answer your question about how photonic crystals can be used to create a super lens, we need to understand the concept of near-field and far-field imaging. In traditional imaging, we use lenses to focus the light from an object onto a sensor or film, creating an image. However, this method has limitations due to the diffraction limit of light, which restricts the amount of detail that can be captured in an image.

In near-field imaging, we use the near-field of an object, which is the region very close to its surface, to capture more detailed information. This is possible because the near-field contains higher spatial frequencies than the far-field, which is the region farther away from the object. However, the near-field signals decay rapidly with distance, making it difficult to capture them.

This is where photonic crystals come in. By creating a photonic crystal with a specific refractive index pattern, we can manipulate the near-field signals and control their decay. This allows us to capture and manipulate the near-field information, essentially creating a super lens that can capture more detailed images than traditional lenses.

I hope this explanation helps you understand how photonic crystals can be used to create a super lens. If you have any further questions, please feel free to ask. Good luck with your project!