Dispersion of optical refractive index of Yb3+-doped laser glass and theirfitting to Lorentzian model

Dispersion of optical refractive index in Yb3+-doped QX/Yb phosphate laser glass was measured from 550 nm to 1200 nm using a spectral dispersive white -light interferometer. The absorption spectrum was also measured and the co mplex optical refractive index was obtained with an accuracy better than 10 (-4). The data were fitted with the Lorentzian interband model, The deviati on of the data calculated using the numerical optimization method from the experimental data was as small as 10(-5) The host and the dopant were defin ed separately in this model. While optical refractive index difference betw een doped and undoped samples was as small as 10-4, the contributions of th e dopant to the higher order dispersion of the refractive index such as dn/ d lambda, dn(2)/d lambda(2), and dn(3)/d lambda(3) were 1.7%, 19%, and 420% , respectively. Additionally, the database with this fitting formula is use ful for different doping concentrations with a proportional change in the c orresponding coefficients. The formula with our fitting parameters will be useful in the design of QX/Yb laser glass based laser systems.