Dear Faiyaz,

One of the optical characteristics of a material is the curve of its absorption coefficient alpha( lambda) as a function of the wavelength of the incident light lambda. When you specify the material, you can search in the web to find absorption curve. The temperature affects the absorption coefficient as it changes its energy band structure which is defining the absorption coefficient. In principle, there will be a red shift by increasing the temperature of the material.

The absorption efficient is defined by the equation:

I(x)=I0 exp - alpha x,

with I(x) is the light intensity at depth x, I0 is the intensity at the surface of the material and X is the path length.

Best wishes

Hello Dr. Zekry, Thank you so much for your kind reply. Can you please tell me if there is any equation that relates absorption coefficient with Temperature?

Dear Faiyaz,

you may refer to the thesis in the link: http://www.dtic.mil/dtic/tr/fulltext/u2/a519309.pdf.

It may contain a quantitative answer to your question.

Best wishes