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Drude-Lorentz and Debye-Lorentz models for the dielectric constant of metals and water

version 1.3 (3.99 KB) by

Computes the complex permittivity of many metals and water with input wavelength

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This code computes the complex dielectric constant (i.e. relative permittivity) and the refractive index of various metals using either the Lorentz-Drude (LD) or the Drude model (D) as a function of input light wavelength.

Additionally, it may compute the dielectric constant of pure water using a Debye-Lorentz model.

Choice of materials: silver, aluminum, gold, copper, chromium, nickel, tungsten, titanium, beryllium, palladium, platinum, triply distilled water.

Reference: Bora Ung and Yunlong Sheng, Interference of surface waves in a metallic nanoslit, Optics Express 15, 1182-1190 (2007).

Comments and Ratings (25)

Thank you.

Bora Ung

Bora Ung (view profile)

Hi André. The resonance frequencies were found in the paper of A.D. Rakić et al., Appl. Opt. 37, 5271-5283 (1998). These characteristic frequencies were extracted from models (Drude and L-D) based on published experimental data for each metals.

Hi, How did you determine the resonance frequencies of the materials?

11 11

11 11 (view profile)

Help me a lot . Thank you .

Rahul Shaw

Helped me. Thanks..

Bora Ung

Bora Ung (view profile)

To Subhashish: in order to obtain the relative permittivity of Chromium at a given wavelength "lambda" (in meters), you should type the following command:

[epsilon_Re epsilon_Im N] = LD(lambda,'Cr')

Not able to run this code as it is. If I want to calculate for Chromium- 'Cr', then what changes have to be done ?

Reda Ahmed

help me please the program don't march

function varargout = LD(lambda,material,model)
 |
Error: Function definitions are not permitted in this context.

i use matlab 2013 b

jimmy

jimmy (view profile)

GG

Qiushi Guo

Extremeley helpful

Hongren

Thank you, very helpful.

scnu

scnu (view profile)

Thanks! It's useful for me.

Rene

Rene (view profile)

Thank you, it is useful for me too.

chao ding

Thanks! It's very useful for me.

Can someone explain to me how to use the code?
Thanks a lot.

Noha Anous

Thanks for uploading such a nice function.
But I have a question, from where are the model equations taken?
are there any approximations?
Because I tried some values and didn't get them the same as I have them in tables found in some papers.
Thanks a lot

Bora Ung

Bora Ung (view profile)

As a note, this matlab code was created for and first used in [B. Ung and Y. Sheng, Optics Express, vol.15, pp. 1182-1190 (2007)]

JCBod Bodoque

Wonderful file! Do you have any work of your own that I can cite for these fits?

j kim

I think, it's good program!!!

Hyunwoo Kihm

Thanks for valuable information with proper references. Weighting factor of various oscillator made the model fitting almost perfect.

Jin Xu

thanks a lot.

Bora Ung

Thanks Duane for the info. I have already done that a few days ago when I realized that it is possible to make changes. Now there IS NO NEED to make any changes.

Duane Hanselman

Rather than tell use what to do to improve the file, why not UPDATE your submission with your latest work? (Do not submit the revised file as a new submission.)

Bora Ung

The efficiency can be improved with the following changes:

replace line 183 with: epsilon_r_L = zeros(size(lambda));
replace lines 185-187 with:
epsilon_r_L = epsilon_r_L + (f(k)*omegap^2)*...
    (((omega(k)^2)*ones(size(lambda)) - omegalight.^2) -...
                i*Gamma(k)*omegalight).^(-1);
eliminate line 190

Hope this file is useful to people as it was to me.

Updates

1.3

Updated the value of the physical constant "ehbar" to a more accurate one. Thanks to A. Webster for the tip!

1.2

A coding error in the previous version is corrected in this version.

1.1

Added a new material (pure water) whose dielectric constant is computed via the Debye-Lorentz model. References are also updated.

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MATLAB 7.4 (R2007a)

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