# How can we calculate the absorption coefficient of the single crystal wafer?

How can we calculate the refractive index and and the absorption coefficient of materials that are thicker than the light wavelength (e.g. very thick film, transparent substrate, bulk single crystal subtrate)?

Is it possible to use the relation: α=1/d*ln(1/T) for calculation like in case of thin films?

Is it possible to use the relation: α=1/d*ln(1/T) for calculation like in case of thin films?

## All Answers (7)

Julien Cardin· Université de Caen NormandieThis same approach can also be used to measure refractive index for thick films.

Julien Cardin· Université de Caen NormandieGasidit Panomsuwan· Chulalongkorn UniversityI have calculated the absorption coefficient of bulk STO single crystal (two-side polishing, 10x10x0.1 mm3) from the transmittance (T) and reflectance (R) spectra using the relation: α=1/d*ln((1-R)^2/T)). However, the calculated value is of the order of ~10^2 cm-1, which is quite different from that obtained by ellipsometry measurement in literatures (~10^5-10^6 cm-1).

Is it correct or not?

Do you have any suggestion?

Julien Cardin· Université de Caen NormandieAnother remark is that since you use double side polish you can assume that you are in a regime of low scattering, which make the work easier.

John Muth· North Carolina State UniversityYuriy P. Gnatenko· National Academy of Sciences of UkraineWael Mohamed· Sapienza University of Romei wonder if i can use the relation α=1/d*ln(1/T) to calculate the absorption coefficient of a bulk material? actually i have only the transmittance data.

Can you help by adding an answer?