Peak Power and Peak Power Density Calculator
Calculate peak power and peak power density for pulsed lasers based on energy per pulse or average power.
Calculation Results
Beam Area
Energy per Pulse
Peak Power
Peak Power Density
How does the Laser Peak Power Calculator work?
The concept of peak power is only useful when considering pulsed lasers. For CW lasers, there will be small fluctuations, but basically, the minimum, average and maximum power of CW lasers are the same. For pulsed lasers, there is a pause time between each small burst of energy that does not emit light. As a result, the minimum power is typically 0 W, while the maximum power peaks when the intensity reaches its maximum. To calculate the peak power of a laser beam, the energy of each pulse must be divided by the duration of the pulse (also known as the pulse width). Then, to find out the peak power density, simply divide the peak power by the area of the beam cross-section at a given distance. Also, if someone already knows the average power of the laser, we can divide it by the repetition rate to find the energy of each pulse. The value of the laser power density also affects how the material reacts to the laser. Of course, pulsed lasers can damage the surface due to the total energy accumulated over a long period of time, but this is related to its average power. Since the energy transfer does not take place in a continuous manner, the surface may also be damaged during each pulse. This can occur if the energy of a single pulse is too high for the material to absorb and diffuse the energy while maintaining its physical integrity. As a result, each pulse blows up a portion of the surface.
Formula for peak power and peak power density
These formulations describe the behavior of a theoretical flat-topped or perfect Gaussian laser beam. As such, they represent an approximation of the values obtained under real-world conditions. In addition, there are various ways to measure the diameter of a Gaussian beam. The main reason for this is that it is only when the radius reaches infinity that its theoretical value is 0. Therefore, the diameter of the beam will be infinite. This led to the choice of using a 1/e² parameter measurement. At this point, the beam diameter is approximately 1.699 times the full diameter measured at half the maximum of the Gaussian function (FWHM). At 1/e², it accounts for about 86.5% of the total power. It is important to note that for flat-topped beams, these formulas can be used as usual, but for Gaussian beams, the right part of these formulas needs to be multiplied by a factor of 2.
\( \text{Peak power density} \left(\frac{W}{cm^2}\right) = \frac{\text{Average power}(W)}{\text{Repetition rate}(Hz) \times \text{Pulse width}(s) \times \text{Beam area}(cm^2)} \)
\( \text{Peak power} (W) = \frac{\text{Energy per pulse}(J)}{\text{Pulse width}(s)} \)
\( \text{Peak power} (W) = \frac{\text{Average power}(W)}{\text{Repetition rate}(Hz) \times \text{Pulse width}(s)} \)