BEGIN:VCALENDAR VERSION:2.0 PRODID:Data::ICal 0.22 BEGIN:VEVENT DESCRIPTION:Lingyun Chai\, University of Virginia - Department of Physics\n \n
We present a te
chnique for measuring the amplitude of weak microwave/rf fields of arbitra
ry frequency. The method uses Rydberg atoms in a vapor cell as a detection
medium\, and electromagnetically induced transparency (EIT) spectroscopy
as an optical readout. Unlike other schemes that rely on resonant coupling
between Rydberg states [1]\, our electrometer is based on non-resonant dr
essing of the Rydberg atoms in combined AC and DC fields. We demonstrate t
he technique in a room temperature Rb cell\, where mixing of the AC and DC
fields through the second-order Stark shift produces sidebands in the EIT
signal\, flanking the primary resonance feature associated with the optic
al 5p &ndash\; 32s transition. The spectral location of the sidebands reve
als the frequency of the AC field. The ratio of the sideband intensity to
that of the central EIT feature gives the AC field amplitude through calcu
lation. Field amplitudes less than 200 mV/cm have been measured at frequen
cies from 20 to 100 MHz. \; \;
\n
\n[1] J. A. Sedlacek e
t al.\, Nat. Phys. 8\, 819 (2012). \;