Time resolved thermal lens measurements of the thermo-optical properties of Nd2O3-doped low silica calcium aluminosilicate glasses down to 4.3K

Influence of temperature and excitation procedure on the athermal behavior of Nd3+-doped phosphate glass: Thermal lens, interferometric, and calorimetric measurements

“…As observed for other glasses, 11,17 D͑T͒ values eventually reach a constant value as the temperature is increased. The thermal diffusivity depends on the average sound velocity s and the phonon mean free path ᐉ as D = ͑1 / 3͒v s ᐉ.…”

“…Although values are expected to be higher as the temperature is decreased, as shown in Ref. 17 for the Nd 3+ doped aluminosilicate glasses, this high value for this glass at room temperature indicates that the mentioned variation may not be significant. Then, we assumed ͑T͒ constant in the temperature range of the experiments, resulting in = 0.57Ϯ 0.04.…”

“…1. 11,17 In this setup, a probe laser beam propagates through the TL sensing the generated optical element, which changes its on-axis intensity, I͑t͒. The detection of the TL signal was performed by a silicon photodiode ͑P 2 ͒, connected to a digital scope.…”

“…In the cw excitation regime, the TL theoretical model provides a simple and analytical expression that links thermo-optical properties of the sample to the time resolved TL transient signal, which is given by [11][12][13][14][15][16][17][18] I͑t͒…”

“…TL spectrometry ͑TLS͒ has been applied to characterize several kinds of materials in a wide temperature range, from 4 to 800 K. [16][17][18][19][20][21] Besides the thermal diffusivity ͑D͒ values, combining the data measured with this method with those by optical interferometry ͑OI͒ ͑Ref. 22͒ and thermal relaxation calorimetry ͑TRC͒, 23 a general picture about the material thermo-optical properties can be obtained, such as the values of ds / dT, k, and .…”