Figure 1
(Top) Thermal length expansion of a 1 mm Si crystal relative to room temperature (squares) fitted by a T2 polynomial (red line). The coloured ellipses show examples of Tp and Tb corresponding to low-, medium- and high-power regimes (green, yellow and red, respectively). Tze shows the temperature of minimum thermal expansion. (Bottom) Schematic representation of crystal deformation, switching from concave to flat, and to convex, when power is increased. |