Figure 3
From: OPM magnetorelaxometry in the presence of a DC bias field
Schematic of the OPM configuration. With a function generator (fgen) and intensity modulator (IM), the linearly polarized light from the laser is pulsed at the Larmor frequency of the alkali atoms and converted into circular polarization by a \(\lambda/4\) waveplate. The transmitted laser light is detected by a photodiode (PD), amplified by a current voltage converter with integrated preamplifier (I/U) and phase-sensitively demodulated with a lock-in amplifier (LIA)