Abstract

Persistent spectral holeburning is known to occur in rare-earth doped silica-based glasses,¹-³ where the mechanism is attributed to light induced changes in the coupling of tunnelling systems (TLS) which are characteristic of the amorphous state. A number of hole parameters such as lifetime, saturation depth and temperature dependence of the width, can provide important information on the density of states and dynamics of the TLS. We present the first data on spectral holeburning in a rare-earth doped heavy metal fluoride glass (HMF, Rennes) and compare with data obtained on a silicate glass (ED-2, Owens-Illinois). For this study we have chosen the well known ⁴I_9/2 ← → ⁴F_3/2 transition of the Nd³⁺ ion whose absorption peaks around 870nm (HMF) and 880nm (ED-2). Previous holeburning and photon echo measurements have been reported on the ⁴I_9/2 ← → ⁴G_5/2 transition of the Nd³⁺ of bulk ED-2 glass⁴ and on the ⁴I_9/2 ← → ⁴F_3/2 transition of the Nd3' transition of a pure silica fiber.³,⁵

© 1992 Optical Society of America