Abstract

Energy upconversion was known to occur in rare earths by ion–ion interactions and sequential two-photon excitation processes.¹ Recently there has been a renewed interest in these studies after the development of upconverted lasers.² The phonon spectrum of the host lattice influences are not only the resonant fluorescence quantum efficiency but also that of upconverted fluorescence and hence the laser efficiency. So far upconverted laser action was seen only in single crystals. To extend these studies to other materials we prepared sodium borosilicate glasses doped with neodymium. All the prominent absorption peaks of Nd³⁺ are identified in this host. When the D and E levels are resonantly excited upconverted violet fluorescence is detected from the L levels of Nd³⁺ in the glass host.

© 1991 Optical Society of America