| Sodium borate glass embedded with Dy3+, Sm3+, and Tb3+ was made by the melt quenching technique. Under 405nm diode laser excitation it revealed strong orange color emission. The CIE color co-ordinates are x = 0.574, and y = 0.400 and the color temperature is 1599K. However, under 375nm diode laser excitation its emission color changed to greenish white. The CIE color co-ordinates are x = 0.448 and y = 0.500 and the color temperature is 3756K. This indicates that the sample emits warm white light. The 405nm laser excites Dy3+ and Sm3+ only whereas the 375nm laser excites Dy3+, Sm3+, and Tb3+ ions. Tb3+ emits predominantly green color. That is why the sample color changed to white under violet laser excitation. The emission wavelengths are unambiguously assigned by measuring the lifetimes of the emission wavelengths. |
