The Titanium Sapphire laser is a transition metal ion laser that provides short pulse operation.  Because of coupling between electronic levels of 3d electrons with lattice vibrations, transition metal ions mostly show broad band emission. The Ti:Sapphire laser has only one d electron, and can only exist in two energy levels. However, as the laser operates on a vibronic transition, it resembles a four-level laser. The possibility of excited state absorption of radiative transitions is eliminated due to the energy level structure of the Ti³⁺ ion, in that it has no d-state energy levels above the upper laser level.

The wide tuning range of the laser is possible because of a large shift between the E_3/2 excited state and the ²T_2g ground state. The upper and lower level of the ²E_g state can be split above the ²T_2g ground state.
 
 

Because absorption for a Ti:Sapphire laser occurs from wavelengths below 450nm up to wavelengths over 600nm (See Fig 3. on previous page), a wide range of pump wavelengths are possible. A short spontaneous emission lifetime has caused the development of the laser to be focused around laser pumping. There are two main lasers used to optically pump the Ti:Sapphire laser: The Argon Ion Laser (ArL), and the Double Neodymium Yttrium Aluminum Garnet Laser (D-YAG). Using a YAG laser produces a short output pulse from the Ti:Sapphire laser. The YAG pump produces a gain pulse that measures changes in gain.