Alexandrite (Laser)
BeAl2O4:Cr3+

Properties

Parameter unit

Values

Molecular weight

 

126.97

Mean dislocation density

cm2

103

Syngony

 

Rhombic

Spatial group

 

Pnma

Unit sell parameters

Å

a = 5.47
b = 9.39
c = 4.42

Refraction indexes

 

Ng = 1.753
Nm = 1.747
Np = 1.744

Density

g/cm3

3.79

Moh’s hardness

 

8.5 

Axial characteristics

 

Biaxial 

Melting point

oC

1870

Thermal conductivity

W/cmoK

0.23

Color

 

Green (for daylight),
Red (for artificial lightening)

Al2O4:Cr3+   PROPERTIES

Cr4+ concentration 

at%

0.03 – 1.0

Stimulated emission cross-section at 300 K

cm2

3.0 ´ 10-19

Lifetime

sec

260 ´ 10-6

Optical loss (l=  750 nm)

cm-1

0.001 - 0.003

Wavelengths of operation in CW and pulsed mode 

mm

0.70 – 0.82

BeAl2O4:Cr3+  LASER RODS

Configuration of rod’s cross section

 

Round

Sizes and processing

 

 

Diameter tolerance

mm

+/- 0.1

Length tolerance

mm

+/- 0.5

Non-parallelism of end faces

 

10”

Surface finish

Scratch-dig

10-5

Flatnes

 

l/10

Orientation tolerance

 

< 0.5o

Rod’s orientation

 

[001]

Diameter

mm

4 – 10

Length

mm

60 - 120