Chrysoberyl modification – Alexandrite (^Cr3+: _BeAl2O4) is both a coveted gemstone and a much sought-after material for solid-state lasers. It is the first solid-state medium that is tunable at room temperature. Alexandrite lasers are vibronic lasers, i.e. both photons and phonons are emitted during the laser process. The tuning of the wavelength can be achieved by changing the energies between photons and photons during laser operation. Alexandrite lasers can be tuned between 701nm and 860nm, with the central tunability range being 720nm – 800nm.

Other wavelengths can be achieved by non-linear frequency conversion such as SHG and Raman shift. These range from the IR range (20µm) to the VUV range. In addition to its broad absorption bands, alexandrite has an absorption close to the R-line near 680nm.

These properties and its long fluorescence lifetime make it an ideal material for a flashlamp pumped or diode pumped system and its thermomechanical properties make it ideal for high energy laser applications.