The beam waist of laser was measured at 11.3 mW and 101 mW of power.

A plano convex lens(f=50mm) was placed at around 100mm after the laser shutter. The evolution of beam size (after the lens) depending on the position was measured. The corresponding plots are here. 

1. P =11.3 mW plot

2. P = 101 mW plot

The beam waist is found to be same for 11mW and 101mW power and is at [56.3,57.5 ± 0.003,0.004] mm for the major and minor axis respectively.

The major and minor axis respectively are [76.5,88.5 ± 3E-6,6E-6] µm at waist