Continuous-Wave (CW) Lasers emit a constant stream of light energy. Power emitted is typically not very high, not exceeding killoWatts. Pulse Lasers were designed to produce much higher peak power output through the use of cyclical short bursts of optical power with intervals of zero optical power output. There are several important parameters to explore in relation the pulsed laser in particular.
The period of the laser pulse Δt is the duration from the start of one pulse to the start of the next pulse. The inverse of the period Δt is the repetition rate or repetition frequency. The pulse width τ is calculated as the 3dB (half power) drop-off width.
The Duty cycle is an important concept in signals and systems for periodic pulsed systems and is described as the ratio of the pulse duration to the duration of the period. Interestingly, the continuous wave lase can be considered as a pulse laser with 100% duty cycle.
Power calculations and Pulse Energy remain as several important relations.
- Average Power: the product of Peak pulsed power, repetition frequency and the pulse width
- Pulsed Energy: Average power divided by the repetition frequency
Other formulations of these parameters are found above.