  There are different methods for finding exoplanets such as radial spectral
shifts, astrometrical measurements, transits, timing etc. Gravitational
microlensing (including pixel-lensing) is among the most promising techniques
with the potentiality of detecting Earth-like planets at distances about a few
astronomical units from their host star or near the so-called snow line with a
temperature in the range $0-100^0$ C on a solid surface of an exoplanet. We
emphasize the importance of polarization measurements which can help to resolve
degeneracies in theoretical models. In particular, the polarization angle could
give additional information about the relative position of the lens with
respect to the source.
