Tellurite And Fluorotellurite Glasses For Active And Passive

6. Optical properties; MDO 218
Absoprtion coefficient / cm -1
1.0 0.9 0.8 0.7 0.6 0.5
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
Untreated
1 hr. 245 o C
1 hr. 255 o C
Wavelength / µm
0.0
10000 12000 14000 16000 18000 20000
Wavenumber / cm -1
Fig. (6.46): Visible spectra of glass MOF017 (69.86TeO2-9.98Na2O-19.96ZnF2-0.20ErF3
mol. %), untreated, and heat treated 1 hour at 245 and 255°C.
It can be seen that the intensity of the absorption bands increased with increasing heat
treatment temperature; also the slope on the background loss increased more at shorter
wavelength – a phenomenon associated with increased scattering loss.
Fig. (6.47) shows the visible spectra of glass MOF017 (69.86TeO2-9.98Na2O-
19.96ZnF2-0.20ErF3 mol. %), heat treated for 1, 5 and 11 hours at 240°C.
1000
900
800
700
600
500
400
300
200
100
0
Loss / dB.m -1