Infrared multiphonon edge

One of the main spectroscopic properties that differentiate fluoride glasses from silica-based glasses is the low multiphonon emission rate. These non-radiative relaxations that may strongly compete with radiative processes in rare-earth ions are nearly three orders of magnitude lower in ZBLAN glass than in silicate, as shown in Fig. 2. This property is directly related to the fundamental vibration modes of the host and, therefore, varies basically in the same manner as the infrared absorption edge. [Pg.243]

These absorptions can be divided into three categories impurity absorptions due to gases or bound hydrogen isotopes, the infrared cutoff or multiphonon edge, and the fundamental structural vibrations. [Pg.216]

Figure 10.4 Infrared transmission spectra showing the shift in the multiphonon edge for glasses of different compositions...