Laser Average Power and Power Density Calculator
Use this online calculator to convert laser average power and energy per pulse to average power density/irradiance and average power. Suitable for Gaussian and flat beam profiles.
Calculation Results
Beam Area
Average Power
Average Power Density
How does the Laser Beam Aperture Calculator work?
When considering a circular Gaussian laser beam, each waveplane it produces (theoretically) has a certain energy value anywhere in the universe. Therefore, if the laser beam passes through the aperture, no matter how large the aperture actually is, there will be a certain amount of incident laser beam energy that does not pass through the aperture. Knowing the diameter of 1/e² of the laser beam, the power passing through the aperture can be calculated. Predictably, the larger the aperture, the more insignificant the proportion of power being blocked. This is important when using detectors, mainly because an inappropriate aperture size can lead to inaccurate power or energy measurements. The same is true when considering the optical design of new technologies. Finally, depending on the measurement accuracy requirements (and the centering position of the beam on the detector), as a rule of thumb, the aperture should be twice the beam size at 1/e². At this point, more than 99.9% of the incident beam power has passed through the aperture (if fully centered).
Formulas
The laser average power formulas describe the behavior of theoretically flat-top or perfect TEM₀₀ Gaussian laser beams. Therefore, they represent approximations of the values obtained under real-world conditions. Furthermore, there are various methods for measuring the diameter of a Gaussian beam. The main reason for this is that its theoretical value only reaches 0 when the radius is infinite. Consequently, the beam's diameter would be infinite. For this reason, we have chosen to use the 1/e² parameter measurement method. At 1/e², the beam diameter is approximately 1.699 times the full diameter measured at half the maximum value (FWHM) of the Gaussian function. At 1/e², it contains approximately 86.5% of the total power. Note that for flat-top beams, these equations can be used as-is, but for Gaussian beams, the right-hand part of these equations needs to be multiplied by a factor of 2.
\( \text{Average power density} \left(\frac{W}{cm^2}\right) = \frac{\text{Energy per pulse}(J) \times \text{Repetition rate}(Hz)}{\text{Beam area}(cm^2)} \)