As the name suggests this laser has a pulse duration that is in the picosecond time regime. Typically, industrial lasers are in the range between 10 picoseconds to 150 picoseconds or 10-150 x 10-12 s. The key concept when moving from nanosecond to picosecond lasers is avoiding the temporal spread of the pulse duration in the cavity that naturally occurs as longitudinal modes that oscillate between the cavity mirrors are uncontrolled. By controlling these modes such that they stack up with constructive and destructive interference, the pulse duration is minimized to a level that is a function of the gain medium - this phenomenon known as mode locking. The most popular gain media for picosecond lasers have a fundamental wavelength in the IR (around 1030-1070nm wavelength). It is possible to convert this wavelength to produce both green and UV wavelengths by using nonlinear crystals. Picosecond lasers are typically selected over nanosecond lasers when the tolerances of the heat affected zone (HAZ) or feature size is critical. The interaction with the material by the shorter pulse duration causes less energy to deposit into the material, thereby reducing the HAZ. Picosecond lasers, along with femtosecond lasers, fall under the umbrella of ultrafast lasers and are selected for micromachining and cutting applications that are not accessible with nanosecond lasers.