Broadband Rydberg Atom-Based Electric-Field Probe for SI-Traceable, Self-Calibrated Measurements

• Published in: IEEE transactions on antennas and propagation Vol. 62; no. 12; pp. 6169 - 6182
• Main Authors: Holloway, Christopher L., Gordon, Joshua A., Jefferts, Steven, Schwarzkopf, Andrew, Anderson, David A., Miller, Stephanie A., Thaicharoen, Nithiwadee, Raithel, Georg
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.12.2014; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Atom based metrology; Atomic beams; Atomic clocks; Atomic measurements; Autler-Townes splitting; Broadband; broadband sensor and probe; electrical field measurements and sensor; electromagnetically induced transparency (EIT); Field strength; Frequency measurement; Imaging; Measurement by laser beam; Probes; Radio frequencies; Radio frequency; Rydberg atoms; Rydberg states; Splitting; Strength; sub-wavelength imaging; Transducers
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2014.2360208

We discuss a fundamentally new approach for the measurement of electric (E) fields that will lead to the development of a broadband, direct SI-traceable, compact, self-calibrating E-field probe (sensor). This approach is based on the interaction of radio frequency (RF) fields with alkali atoms excited to Rydberg states. The RF field causes an energy splitting of the Rydberg states via the Autler-Townes effect and we detect the splitting via electromagnetically induced transparency. In effect, alkali atoms placed in a vapor cell act like an RF-to-optical transducer, converting an RF E-field strength measurement to an optical frequency measurement. We demonstrate the broadband nature of this approach by showing that one small vapor cell can be used to measure E-field strengths over a wide range of frequencies: 1 GHz to 500 GHz. The technique is validated by comparing experimental data to both numerical simulations and far-field calculations for various frequencies. We also discuss various applications, including: a direct traceable measurement, the ability to measure both weak and strong field strengths, compact form factors of the probe, and sub-wavelength imaging and field mapping.