  We have designed and tested an automated simple setup for quickly measuring
the profile and spot size of a Gaussian laser beam using three cost-affordable
light sensors. Two profiling techniques were implemented: imaging for the CMOS
2D array (webcam) and scanning knife-edge-like using a single photodiode and an
LDR. The methods and sensors were compared to determine their accuracy using
lasers of two different wavelengths and technologies.
  We verify that it is possible to use a low-cost webcam to determine the
profile of a laser with 1% uncertainty on the beam waist, 1.5% error on the
waistline position, and less than 3% error in determining the minimum spot
radius. The photodiode measurement is the most stable since it is not affected
by the change in laser intensity. In addition, we show that it is possible to
use an inexpensive LDR sensor to estimate the laser spot size with an 11%
error.
