Interferometric technique for investigation of nonradiative transition kinetics in silica-fiber laser media

A novel tool for investigation of nonradiative processes in active solid-state laser media is proposed. The technique is based on using an interferometer for population-kinetics detection by means of resonantly enhanced nonlinearity. The advantages of this method in comparison with traditional luminescence-kinetics techniques are verified on the example of decay time measurements for nonradiative 4I(11/2)→4I(13/2) transition in an Er3+-doped active optical fiber.