All solid-state laser marking systems are nanosecond lasers. Nd:YAG lasers are typically 10 to 150 nanoseconds and vanadate lasers are 5 to 30 nanoseconds. The pulse width of these two lasers becomes longer as the frequency increases. The pulse width of the fiber laser is either fixed in the range of 100 nanoseconds or by using a main oscillator fiber power amplifier (MOFPA) to vary the pulse width from 10 to 200 nanoseconds. The pulse width affects the thermal penetration depth of the material. Short pulses are ideal for sensitive applications such as day and night clean ablation of the ink layer and metal marking of low heat affected areas (HAZ). An example of such an application is marking on stress components in the aerospace industry. For plastics, there are no general rules, some for long pulses and some for short pulses.