Co:MALO (Co:Spinel) Passive Q-Switch crystals
Co:MgAl2O4 (known as both Co:MALO or Co:Spinel) - a spinel crystal doped with Cobalt - is a recently developed material which has been proven to be a very effective passive Q-switch in lasers emitting in the range 1.2 - 1.6µm.

It is widely used in eye-safe Er:Glass lasers, (1.54µm) but also proven with laser operating at 1.44µm and 1.34µm wavelengths.

Co:MALO (Co:Spinel) has a high absorption cross section which permits Q-switching of Er:Glass laser (both flash-lamp and diode-laser pumped), without intra-cavity focusing, Negligible excited-state absorption results in high contrast of Q-switch, i.e. the ratio of initial (small signal) to saturated absorption is higher than 10.

Co:MALO crystal strengths include:
  • Low optical losses over the range 1.3 to 1.6µm
  • High optical damage threshold

Co:MALO crystal applications include:
  • Passive Q-switch for Nd:YAG @ 1.32µm , 1.44µm
  • Passive Q-switch for Iodine @ 1.31µm
  • Passive Q-switch for Er:Glass @ 1.54µm
Request Quote
Co:MALO / Co:Spinel Crystal - Availability
  • Format:
Rods, Discs and Slabs
  • Sizes:
Cross-section: 14 x 14mm max and Length: 12mm max
Co:MALO Crystal Properties
Optical Properties Units Value
Optical Transmission µm 1.3 - 1.6
Doping Concentration mol% 0.03 - 0.65
Initial Transmission % 5 - 95
Transmission/
Transparency Range		 nm 155 - 3200
Optical Homogeneity (δn) cm‾¹ ~ 10‾⁶
Refractive Index (n) cm‾¹ 1.6 - 1.75
Absorption Coefficient @1064nm cm‾¹ 0.001
Physical / Thermal Properties Units Value
Chemical Formula Co:MgAl2O4
Crystal Symmetry/
Structure		 Cubic
Space Group
Point Group
Melting Point ºC 2105
Thermal Expansion Coeff. @20ºC 10‾⁶/ºC 7.33
Thermal Conductivity Coeff. @20ºC W/m/ºK 17
Specific Heat Capacity J/g K TBA
Density g/cm³ 3.58
Mohs Hardness 8
Optical Damage Threshold @1064nm,1ns MW/cm² 500
Further Reading / Publications