  We demonstrate improved sensitivity of Rydberg electrometry based on
electromagnetically induced transparency (EIT) with a ground state repumping
laser. Though there are many factors that limit the sensitivity of radio
frequency field measurements, we show that repumping can enhance the
interaction strength while avoiding additional Doppler or power broadening.
Through this method, we nearly double the EIT amplitude without an increase in
the width of the peak. A similar increase in amplitude without the repumping
field is not possible through simple optimization.We also establish that one of
the key limits to detection is the photon shot noise of the probe laser. We
show an improvement on the sensitivity of the device by a factor of nearly 2 in
the presence of the repump field.
