Photons emitted by the doped sapphire crystal are guided through the resonator cavity by reflection from the surface of routing mirrors. Other elements in the 10-mirror folded cavity include rod focusing mirrors, an output coupler, a high reflector, beam folding mirrors, dispersion control prisms, and a tuning slit for adjusting the output wavelength. Before final output, the laser beam passes through a beam splitter where a portion of the light is diverted to a fast photodiode that is coupled to an electronic clocking circuit through a feedback loop. Finally, the beam travels through a Brewster output window to exit the laser cavity housing.
Several sliders control laser parameters that serve to modify how the applet functions.
The Pulse Width slider can be utilized to adjust this value between 30 and 150 femtoseconds, and the Wavelength slider operates the tuning slit to vary output wavelengths from 690 to 1050 nanometers. A third slider controls the applet run speed. Note that the lowest pulse width attainable in the actual Spectra Physics laser is 50 femtoseconds. To ensure proper cooling and humidity control of the laser crystal, nitrogen gas is pumped into the sealed laser head, which is maintained at constant temperature by an external chiller. The Titanium trivalent cation is responsible for laser action in doped sapphire crystals, which are produced by introducing titanium oxide into a melt of aluminum oxide.