Calculation of material properties in transformation media

In summary, the conversation discusses meta-materials and the components of the permittivity tensor as given in Schurig's paper. It also mentions the transformation matrix for a cylindrical cloak and the difficulties in finding the material properties using different formulas. The conversation ends with a request for help in understanding the calculation of material properties in transformation optics.
  • #1
radiofeda
5
0
Hi everybody,

I'm focusing on meta-materials. I have recently read Schurig's paper "http://www.opticsinfobase.org/oe/abstract.cfm?URI=OPEX-14-21-9794"). In the article, the components of the permittivity tensor are given by
[tex]\varepsilon^{i'j'} = \left|\rm{det}(\Lambda^{i'}_{i})\right|^{-1} \Lambda^{i'}_{i} \Lambda^{j'}_{j} \varepsilon^{ij}[/tex]
where the Jacobian matrix
[tex] \Lambda_{\alpha}^{\alpha'} = \frac{\partial x^{\alpha'}}{\partial x^{\alpha}} [/tex]
and the roman indices run from1 to 3, for the three spatial coordinates, as is standard practice.

Working out the algebra, the components of the permittivity (permeability) tensor can be obtained by
[tex] \left(\varepsilon^{i'j'}\right) = \left|\rm{det}\left(\Lambda\right)\right|^{-1}\Lambda^T \Lambda
[/tex]
where [tex] \Lambda [/tex] is a matrix, which components are the counterpart of the contravariant coefficients [tex] \Lambda_{\alpha}^{\alpha'} [/tex].

For cylindrical cloak, the components of the transformation matrix are
[tex] \left(\Lambda^{i'}_{j}\right) = \left(
\begin{array}{ccc}
\frac{\rho'}{\rho}-\frac{ax^2}{\rho^3} & -\frac{axy}{\rho^3} & 0 \\
-\frac{ayx}{\rho^3} & \frac{\rho'}{\rho}-\frac{ay^2}{\rho^3} & 0 \\
0 & 0 & 1 \\
\end{array}
\right)
[/tex]
It is easy to find the material properties. For instance, the z component of the permittivity tensor is
[tex]\varepsilon_z = \varepsilon^{3,3} = \frac{\rho^2}{\rho'(\rho'-a)} = \frac{1}{\left|\rm{det}\left(\Lambda\right)\right|}[/tex]

However, in the paper "http://pre.aps.org/abstract/PRE/v74/i3/e036621" ), the components of the relative permittivity and permeability tensor specified in cylindrical coordinates are given
[tex]\varepsilon_z = \mu_z = \left(\frac{b}{b-a}\right)^2 \frac{\rho-a}{\rho}[/tex]

It can be seen that the two formula are not equal obviously. And the other nonzero components of the permittivity and permeability tensor are not equal too.

I have deduced the formulas for many times. Depressingly, I can not figure out the problem. Could somebody please give me some comments on the calculation of material properties in transformation optics.

Regards.
 
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  • #2
I just glanced through the papers, but I wonder if you are looking in the wrong place: see, for example, eqns 20-22 and 29-30 in the OE paper.
 
  • #3
Andy Resnick said:
I just glanced through the papers, but I wonder if you are looking in the wrong place: see, for example, eqns 20-22 and 29-30 in the OE paper.
I see. However, it seems not easy to obtain eq.(29) from eq.(26) by applying eq.(6) or (7).
 

1. What is the purpose of calculating material properties in transformation media?

The purpose of calculating material properties in transformation media is to understand how different materials behave when undergoing a transformation. This can help scientists and engineers design and develop new materials with specific properties, such as shape-shifting capabilities or improved strength and durability.

2. What are some common transformation media used in material property calculations?

Some common transformation media used in material property calculations include polymers, metals, ceramics, and composites. These materials undergo various transformations, such as phase changes or structural changes, which can significantly impact their properties.

3. How are material properties measured in transformation media?

Material properties in transformation media are typically measured through experiments and simulations. Experiments involve physically testing the material under different conditions, while simulations use models and equations to predict the material's behavior. Both approaches provide valuable data for calculating material properties.

4. What factors can affect the accuracy of material property calculations in transformation media?

Several factors can affect the accuracy of material property calculations in transformation media. These include the quality and consistency of the input data, the complexity of the transformation process, and the limitations of the chosen calculation method. It is essential to carefully consider these factors and their potential impact on the results.

5. How can the calculated material properties in transformation media be applied in real-world applications?

The calculated material properties in transformation media can be applied in various real-world applications, such as developing new materials for aerospace, automotive, and medical industries. They can also be used to improve existing materials, such as creating stronger and more lightweight metals for construction and transportation. Additionally, understanding material properties in transformation media can aid in predicting and preventing material failure and improving the overall performance of materials.

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