Question

how to find r.i (n) of thin film from A, R%,T% data?

I have absorbance, reflectance% and transmittance% data. How to calculate refractive index from this.
I tried with R = [(n - 1)^2 + K^2 ] / [(n + 1)^2 + K^2] where K is extinction coefficient.
Calculation was done by numerical method. It shows large deviation from reported value.
Kindly suggest how to proceed.

Topics

2 / 1  ·  16 Answers  ·  683 Views

• Anwar Rana · Bahauddin Zakariya University
The complex refractive index n∗ is defined as:
n∗ = n − i k,
The refractive index n is determined from reflectance R using the relation:
n =[(1 +√R)/(1 −√R)]
and extinction coefficient k is given by the relation:
k = αλ/4π
Absorption coefficient α is determined from transmittance T by the relationship:
T = exp(−αx), or α = [ln(1/T )]/x
• Muhammed Ali A.V · Manipal University
Use swanepoel method if u know the refractive index of the substrate
• Mahesha M G · Manipal University
Ali,
I want to know how to get from the eqn I mentioned above or any other method which uses R and A
• Jose Castellanos · Electric Machinery / GE
Do you have data of R and K ? Then use trial and err method. Otherwise I do not get your issue with the equation. Regards.
• Ijaz Talib · Bahauddin Zakariya University
Try, (i suppose there is no energy loss from the eam used due to dispersion and scattering in your material)
• Ijaz Talib · Bahauddin Zakariya University
* eam=Beam
• Ijaz Talib · Bahauddin Zakariya University
In general, ref. Index is a function of the wavelength of the incident light, so keep in mind the wavelength at which you are comparing your value with an other .
• Adal Arasu · St. Joseph's College of Tiruchchirappalli
Hi u can easily find the refractive index as well as thickness of the thin film by using swnepoel method..... By using this method you can find refractive index from transmittance data,,,,,,
• Naidu Revathi · Tallinn University of Technology
HI

Using swanepoel method you will calculate the optical constants.
I am herewith attaching the swanepoel paper for your review.

I hope it will helps you.

Good Luck
• Ramakrishna Madaka · Indian Institute of Technology Guwahati
hi Naidu Revati mam,
i was very happy to suggest this paper for finding the optical constants.......
as per my knowledge in this paper in equation 22 is not correct it should be (n+1)^3
• Mohammed Razooqi · University of Tikrit
Dear Naidu
best wishes
• Adal Arasu · St. Joseph's College of Tiruchchirappalli
Hi friends....
Can you suggest , how to determine the electro chromic properties of thin film from the cyclic voltometer studies...
• Ahmed Naji · Beni Suef University
Data is the master. If your are sure about your measurements and calculation method, you must be confident about your result. Do not be panic if your results disagree with published values since your deposition technique should have some finger print on the samples.
• E. Sheregii · Rzeszów University
One of methods to find the refractive index is to measure the reflection coefficient R(w) in the far infrared region after phonon frequency - normally w=200 -300 cm-1. Because R(w)= ((n-1)/n+1))2, you can calculate the refractive index n.
• Mahesha M G · Manipal University
Thanks
• Leke Olarinoye · Federal University of Technology Minna