  Smartphones may be seen as miniature toolboxs to perform Physics experiments.
In this paper, we present three different "optics workbenches" mainly based on
the light meter of a smartphone. One is aimed at the precise study of Malus law
and other effects associated to linearly polarized light, the second allows
quantifying the light intensity distribution of diffraction or interference
patterns projected on a screen, and the third demonstrates the so-called
inverse square law obeyed by the light from a pointlike source. These
experiments allow to quantitatively demonstrate three fundamental laws of
optics using quite inexpensive equipment.
