Thermal-Diffusivity Dependence on Temperature of Gadolinium Calcium Oxoborate Single Crystals

D Trefon-Radziejewska,J Bodzenta,T Łukasiewicz

doi:10.1007/s10765-012-1197-x

Abstract

Thermal diffusivities of pure and doped gadolinium calcium oxoborate (GdCOB) single crystals were measured as a function of the temperature along optical indicatrix axes X, Y, and Z. Three GdCOB samples were investigated, chemically pure single crystal, the one doped with 4 at% of Nd and the next one doped with 7 at% of Yb. Measurements were carried out for temperature range 40 °C to 300 °C. Determination of the thermal diffusivity based on an analysis of thermal wave propagation in the sample. For a detection of temperature disturbance propagating in the sample the mirage effect was used. Obtained results show that the thermal diffusivity decreases with the increase of sample temperature for all investigated crystals. The GdCOB single crystals reveal a strong anisotropy. The thermal diffusivity along Y direction has the highest value while values obtained in X and Z axes are much lower. Dopants cause decrease in the thermal diffusivity for all investigated directions.

Highlights

In the last decade demand for application of nonlinear optical materials in laser systems has been increasing
From the slope of the line fitted to the experimental points, the thermal diffusivity was calculated
The obtained results confirm that GdCOB crystals exhibit strong anisotropy of the thermal diffusivity connected with their monoclinic structure

Summary

Introduction

In the last decade demand for application of nonlinear optical materials in laser systems has been increasing. Pure and rare-earth ion-doped GdCOB crystals possess many interesting physical properties such as a high-nonlinear coefficient, high-damage threshold, high-optical gain at 1.06 μm, and low self-absorption at the second-harmonic wavelength [2]. They find applications as efficient crystals for frequency conversion and self-frequency doubling laser [3]. Optical nonlinearity makes them interesting as materials for color displays, high-density optical data storage devices, laser printers, biotechnology, and eye-safe light generation [4,5,6] Considering application of these crystals in laser techniques, it is crucial to investigate their thermal properties.

Samples

Measuring Method

Experimental Setup

Results and Discussion

Conclusion