Laser ceramics Tm:Lu2O3. Thermal, thermo-optical, and spectroscopic properties

In this paper we report the measurements of in-plane thermal diffusivity, lifetime of metastable level 3F4, thermal coefficients of linear expansion and refractive index change of laser ceramics Tm(2 at.%):Lu2O3 by the transient grating technique. The wavelengths 213, 266, 355 and 796 nm from pulsed lasers were chosen for sample excitation in accordance with the desire to measure particular parameters. The experimentally determined thermal diffusivity 0.05 cm2/s was attributed to subsurface layer, which has thickness of order of grating period. The applied approach ensured more reliable measurement of lifetime of metastable 3F4 level as compared to the conventional luminescence detection. The dynamic value of linear expansion coefficient was measured under sample excitation at 213 nm and was found to be close to that as measured elsewhere in static regime. Coefficient of refraction index change was found to be as high as 2 × 10−5 K−1.The value of absorption coefficient of ceramics at 213 nm was estimated by excitation of acoustic grating in a thin layer of air adjacent to the sample surface. After the estimation, it exceeded 104 cm−1.

Graphical abstractThe optical response of Lu2O3 ceramics surface to spatially modulated pulsed excitation at wavelength 213 nm. The amplitudes and frequencies of oscillations in MHz band contain the information on mechanical properties, coefficient of absorption, coefficient of thermal expansion of sample and the temperature of its surface at the moment of light action.Figure optionsDownload full-size imageDownload high-quality image (115 K)Download as PowerPoint slideHighlights► Multiple characterization of laser ceramics Lu2O3 by the transient grating technique. ► Sound in air was applied for coefficient of absorption of more than 104 cm−1 estimation at 213 nm. ► The in-plane thermal diffusivity of thin subsurface layer in the sample was determined. ► Dynamic coefficient of thermal expansion and coefficient dn/dT were measured. ► Color centers generation was observed in ceramics under hard UV excitation.