Passive Q-switches or saturable absorbers generate high power laser pulses without the use of electrooptic Q-switches, thereby reducing the package size and eliminating a high voltage power supply. Co2+:Spinel (MgAI2O4) is the material of choice for the important eye-safe wavelengths near 1.5 microns. It has useful absorption that covers 1.2 to 1.6 micron laser transitions. Spinel is a hard, stable crystal that polishes well. Cobalt substitutes readily for magnesium in the Spinel host without the need for additional charge compensation ions. A convenient measure of the Co2+ concentration is the low power absorption coefficient at, for example, 1533nm, a typical wavelength for Erbium doped phosphate glass. SYNOPTICS grows crystals for passive Q-switches with á values from about 0.5 to 3 cm -1 . The actual Co 2+ ion density N in the crystal can be calculated from N = / G SA where G SA is the ground-state absorption cross-section with a value 1 of 3.5 x 10 -19 cm 2. This absorption is high enough to permit Q-switching of Erbium glass without intracavity focusing. Passive Q-switches are typically specified by the low power Optical Density (or %T) at the laser wavelength. SYNOPTICS measures the value in the crystal and adjusts the part thickness to the optical density specified. Thickness is therefore a free parameter, but typically 1 - 5 mm. Specifications SYNOPTICS Standard flat / flat Damage Threshold: Customer Values K.V. Yumashev, Applied Optics 38, No. 30 (1999) 6343-6346. Specifications and information are subject to change without prior notice. © 2011 Northrop Grumman Corporation 1-704-588-2340 • FAX 704-588-2516 1201 Continental Blvd., Charlotte, NC 28273 Email: [email protected] Website: www.as.northropgrumman.com/synopt