Abstract

As a class of laser crystals, the Cr³⁺ -doped lasers offer enormous potential for highly efficient, tunable, visible, and near-IR output under diode-pumped conditions. Such lasers are consequently appropriate for a wide range of applications. Diode-pumping of a Cr³⁺-doped laser was first reported¹ for alexandrite using two geometrically coupled, 680-nm laser diodes. In addition, diode-pumping of Cr³⁺ LiSrA1F₆ (Cr:LiSAF) was recently reported.² Cr³⁺ LiCaA1F₆ (Cr:LiCAF), ivith a laser tuning range³ of 720840 nm, a stimulated emission cross-section of 1.2 × 10⁻²⁰ cm², and a spontaneous lifetime of 175 μs, is of particular interest for applications for which alexandrite is well suited, including lidar and near-IR illumination. In this work, we report the first operation of a Cr:LiCAF laser, pumped by laser diodes. Diode-pumping was achieved by combining the output of two 10-mW, 673-nm laser diodes. The pump geometry used is similar to that used to end-pump Nd:YAG lasers, utilizing polarization combination of the two pump diodes. Unlike alexandrite, polarization combination is an effective technique for Cr:LiCAF, because the absorption coefficients for the σ and π pump polarizations are similar.

© 1991 Optical Society of America