LIDAR, light detection and ranging, is an optical remote sensing technology which analyses the properties of scattered light to find range or other information about a distant target. In most LIDAR applications one uses pulsed lasers due to their timing resolution and their high power. Very frequently, however, these pulsed lasers have to emit at a very precise wavelength. In order to achieve the desired wavelength stability, one uses cw diode lasers to seed the pulsed laser with stable laser light. Sometimes, the seeding lasers are even locked to external references like Fabry-Perot Interferometers, wavelength meters or atomic transitions. For laser ranging, the distance to an object is determined by measuring the “time of flight”, the time it takes for the laser pulse to travel from the sender to the object and back.  Measuring both, the time delay and the scattered or intensity of a laser pulse that is resonant to a transition of a certain atom or molecule, one can measure the spatial (distance) dependence of its density. Amongst others, LIDAR technology has applications in geology, seismology, remote sensing and atmospheric physics.