As far as I know, transmittance equals e^(-αx), where α is absorption coefficient and x is thin film thickness(100-300nm). My team and I have engineered a way to find absorption. Transmittance, T= (Output intensity)/(initial intensity), . And, absorption, A=(initial intensity-output intensity)/(initial intensity). After simplifying the equation, one should get A= 1-T.
The problem I am facing is I do not know any equation, which will give me reflectance of Ti as a function of thin film thickness at 808nm wavelength. If someone gives me an equation of transmittance, please include the effects of absorption so that I can calculate the reflectance afterwards.