  Imaging the planets that orbit around other stars requires blocking the host
star which is usually 8-10 orders of magnitude brighter than the planets. This
is achieved with the help of a stellar coronagraph. In the current work, a
concept of a new type of stellar coronagraph is introduced where the star light
is blocked by a linear polarizer in the collimated beam. It is based on
differential rotation between the linear polarization state of planet light and
that of star light. This is achieved with the help of a set of thick
birefringent crystals in the collimated beam of a telescope where the planet
light is made to travel extra optical path length compared to star light. By
adjusting the orientation and thickness of the crystal, the optical path length
can be made to cause a phase difference of {\pi}, just enough to rotate the
initial plane of polarization by 90{\deg} for planet-light without affecting
the star light. Theoretical calculations involving the phase difference due to
birefringent crystals are presented here along with the basic configuration and
design. It is shown that the design blocks the star light identically at all
wavelengths. Application of this concept for detecting Earth-like extrasolar
planet is discussed using a one-meter class telescope.
