A device for sensing a microwave magnetic field polarization component (B−, Bπ, B+) of a microwave relative to a static magnetic field B0, comprising a preparation means to prepare atomic vapor (10) comprising thermal atoms in a first hyperfine state, particularly a dark state to applied laser light, which first hyperfine state is split from other hyperfine state due to zero-field hyperfine splitting and/or due to a static magnetic field (B0) generated by preparation means, at least one cell enclosing the thermal atoms (10), the microwave is adapted to drive Rabi oscillations of thermal atoms between first hyperfine state and second hyperfine state, Rabi frequency of Rabi oscillations being proportional to magnetic field polarization component (B−, Bπ, B+) of the microwave, and imaging means to capture state image of plurality of atoms representing spatial atomic density distribution (Ne) as a function of the Rabi frequency (Ωi(r)) of Rabi oscillations.