Chrysoberyl modification - Alexandrite (Cr3+: BeAl2O4) is a particularly attractive precious gem and. It is also a uniquely versatile solid-state laser material. It has the distinction of being the first solid-state laser medium capable of tunable operation at room temperature. Alexandrite lasers are vibronic lasers; that is, photons, as well as phonons, are emitted during lasing. The wavelength tuning is accomplished by controlling the branching of energy between phonons and photons during lasing. Alexandrite lasers have been tuned across most of the spectrum between 701nm and 860nm. The central part of the tuning range is from 720nm - 800nm.


Using non-linear wavelength conversion processes such as harmonic generation and Raman shifting, light has been generated at wavelengths from the deep IR (20µm) to the VUV. In addition to its broad absorption bands throughout the visible spectrum, alexandrite exhibits narrow R line absorption features at wavelengths near 680nm.


These properties together with its long fluorescence lifetime make it an excellent material for both flash lamp and diode pumping. Alexandrite's thermo-mechanical properties make it an excellent performer in high power laser applications.

Optical and spectral properties
Refractive index @750 nm
1,737 (∥ a-Achse)

1,742 (∥ b-Achse)

1,735 (∥c-Achse)

dN/dT in 1/K
Physical properties
Density in g/cm3
Melting point in °C
Crystal structure
Thermal conductivity in W/(m · K)
Thermal expansion in 1/K
5,9·10-6 (∥ a-axis)

6,1·10-6(∥ b-Achse)

6,7·10-6(∥ c-axis)

Vickers hardness in kg/mm2
Lattice constant in Å
a = 5,47

b= 9,39


Fluorescence lifetime in µs
Dopant concentration in at.%
0,03 ‐ 1,0