Abstract

We discuss the nature of the excited states of the NIR laser center in Cr:YAG. Recent results show that this particular center behaves in a similar manner to that of a Cr:alexandrite laser, inasmuch as the first excited state can be considered to be a "storage level" during room temperature laser operation. This follows from NIR laser excitation studies that show the observed low temperature sharp lines at 1277 and 1280 nm are true zero-phonon lines. The first excited state is found to be a doublet, with a splitting of 30 cm^-1. These new measurements also lead to a new estimation of the absorption cross-section at 1.064 μm (2 × 10^-17 cm²). This relatively high cross-section may affect the choice of the optimum pumping geometries and crystal dimensions as the understanding of this laser system matures. We will also present some laser performance measurements for this system. Finally, we will compare the energy levels of several d² transition metal ions and attempt to show the relationships and correlations between them.

© 1992 Optical Society of America