### How to model laser beam propagation in OpticStudio: Part 1 ...

Mar 31, 2021· Measured 5 mm from laser output: Beam diameter = 2 mm Measured divergence = 9 mrad Knowing the wavelength and the far field divergence angle, using equations (1) through (3), the beam waist is calculated to be 0.0125 mm, with a Rayleigh range of 1.383 mm. We will focus the beam using a singlet lens.