Laser Beam Divergence Calculator

Calculate Laser Beam Divergence

e.g., 1.5 mm
e.g., 10.2 mm
e.g., 5000 mm (or 5 m if D1/D2 were in m)

Results

Laser Beam Divergence (θ): radians

Utilize our Laser Beam Divergence Calculator to quickly determine the angular spread of your laser beam. Essential for optical system design, free-space communication, and understanding beam propagation, this tool helps engineers and researchers evaluate beam performance accurately by simply inputting initial and final beam diameters and the propagation distance.

Formula:

The full-angle laser beam divergence (θ) is calculated using the following practical formula:

θ = (D2 - D1) / L

  • θ: Laser beam divergence (in radians)
  • D2: Beam diameter at the second, more distant measurement point
  • D1: Beam diameter at the first, closer measurement point (e.g., at the source or aperture)
  • L: Distance between the first and second measurement points

Important: Ensure that all input units for D1, D2, and L are consistent (e.g., all in millimeters or all in meters) for an accurate result in radians.

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