Nd:YAG lasers without thermally induced lenses

In particular, the thermal dispersion dn/dT was extrapolated to vanish (dn/dT/spl ap/0) at temperatures around 80 K and at the same time the heat conductivity is 5 times higher as compared to the value at room temperature. In the present work we verified this behavior with experimental investigations and demonstrated a substantial reduction of the thermally induced lenses that led to exceptionally wide power ranges for stable fundamental-mode laser operation in a simple end-pumped laser. The results are of particular interest for spaceborne applications where low temperatures are easily maintained.