CW simply stands for continuous wave. This in turn refers to the that fact that the light output intensity (energy) is constant over time and characterized by the amount of power it generates in Watts (W). An example of a CW laser is the laser pointer which emits a continuous beam of low power visible light. But, they can also be very high power, up into the 1000's of Watts.
A CW laser is a continuous wave (or constant wave) laser. This acronym is simply used in order to classify "CW" lasers separately from pulsed lasers. A pulsed laser has an output which is designed to turn on / off at a specific repetition rate. The acronym "CW" stands for "continuous wave". Producing a CW laser output can be accomplished with different types of materials. These materials include gas, crystals and various semiconductor materials. This tutorial will focus on CW lasers produced by diode pumping solid state materials (CW DPSS lasers) and CW fiber lasers.