Spectral Separation of Up-Conversion Luminescence Processes

Here, we present a novel method for the separation of overlapping emission spectral lines corresponding to nonlinear processes, which differ by effective nonlinearity with respect to the pump field power. The method exploits the factorization of wavelength and pumping power dependencies of the components processes contributions to the total luminescence. The advantage of our method is an ability to be self-testing and robust with respect to noise and experimental imperfections. We successfully demonstrate functionality of the method in the experiment with up-conversion luminescence of the fluorophosphate glass doped with rare-earth ions Yb3+ and Tm3+ pumped by 975 nm CW diode laser.