| Abstract: | We developed a SERF (spin exchange relaxation free) magnetometer using one laser with a circularly/linearly polarized beam. This technique allows us to simplify low magnetic field measurements without losing too much sensitivity. Classic Mx magnetic field modulation enables us to measure the resonance response of atomic vapor polarization. We use a Floquet theory to get a fast numeric solution for the Bloch equations that describe our system. This method enables us to solve the equations with parameters traversing the rotating wave approximation limits and it enables us reaching a fast solution for the zero resonance lines without implementing direct ODE calculation. Zero resonance mode of work allows us to perform an RF modulation of the magnetic field with low frequencies thus enabling us to work in the SERF regime. The SERF regime delivers a much better sensitivity than a parallel regular regime. A differential measurement reduces several types of noises and improves the signal. We here present measurements of birefringent absorptivity for alkali polarized vapor in different alkali densities. As it was predicted for the SERF regime, we measured a typical absorption signal for this process and it had both first and second harmonics related to the Larmor frequency in the presence of magnetic field. Due to the anisotropic nature of birefringent absorptivity, we could use it to derive the direction of the measured magnetic field, i.e. new vector magnetometric measurement in the SERF regime. It is interesting to use the differential measurement geometry in a novel, pump only, implementation. We present calculations and simulations for new magnetometric measurements having Bessel beam geometry. We here show that this optical setup is more effective than known diverging beam setup at the most physical conditions, and has more useful features at 3D measurement. Also, several experimental methods for Bessel
beam measurements are proposed. |
