Beam Divergence and Diameter Calculator
Calculate laser beam divergence (half-angle) and diameter easily with this online tool.
Calculation Results
Beam Divergence (Half-Angle)
How does the Laser Beam Divergence and Diameter Calculator work?
In optics, laser beam divergence refers to the degree to which a beam of light diffuses over a certain distance. Imagine a cone with the theoretical origin of the laser beam at its tip (the diameter of the laser beam is precise here). If you measure the angle between two vectors, one from the top of the cone to the center of the base, and the other from the top of the cone to the side of the base, then the resulting angle is the so-called divergent half-angle. Obviously, the full width is twice as much. Then, knowing only three of the four parameters—the initial diameter, the final diameter, the distance between the diameters, and the divergence angle—will give you all the information you need to calculate the fourth parameter. Also, if you understand the diagram clearly, you realize that the initial diameter can actually be any diameter along the Z axis, not necessarily the diameter at the laser exit.
Formulas for Beam Divergence and Diameter
As with all of our laser calculators, we assume that the shape of the beam is a perfect TEM₀₀ Gaussian beam and that the divergence is constant. This means that we also assume that both diameters are in the same homogeneous, continuous, and isotropic medium. Otherwise, the divergence would be a function of space and therefore not constant. These formulas can be used to calculate the laser beam diameter and divergence (half-angle).
\( \text{Beam diameter}(m) = 2 \times \text{Distance}(m) \times Tan(\text{Divergence(half-angle)}) + \text{Initial diameter}(m) \)