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

Abstract

Abstract-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, selfcalibrating 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 (EIT). In effect, alkali atoms placed in a vapor cell act like an RFto-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.Keywords: atom based metrology, Autler-Townes splitting, broadband sensor and probe, electrical field measurements and sensor, EIT, sub-wavelength imaging, Rydberg atoms

Radio-frequency-modulated Rydberg states in a vapor cell

“…These efforts are further motivated by a broader initiative towards establishing atomic measurement standards for field quantities [1,7,8]. A significant appeal of the demonstrated technique for measurements of microwave fields is that it offers a wide dynamic range in both field strength and frequency, from tens of GHz up to the sub-THz regime [9,10]. Another noteworthy benefit is that Rydberg EIT experiments can be performed in a room-temperature vapor cell and without laser cooling or particle detection methods, resulting in a significantly simplified system.…”

Assessment of Rydberg atoms for wideband electric field sensing

“…The interaction strength between the field and sensing element can be characterized by the material's susceptibility, χ. One difference between EO crystals and a Rydberg vapor is that crystals typically use a second order χ (2) nonlinearity while Rydberg vapors rely on a third order χ (3) due to the vapor's spatially centrosymmetric nature nullifying its χ (2) response.…”

Rabi resonance in Cs atoms and its application to microwave magnetic field measurement

“…Recently, atom-based microwave (MW) measurement has also inspired great interest because of its potential ability to link the MW quantities with SI units. As a result, relying on various physical principles, many atom-based MW sensors have been developed [1], such as the MW power standard [16][17][18][19], MW electrometry [20][21][22][23][24][25][26][27][28][29][30][31][32], MW electric/magnetic field imaging [22,[33][34][35][36][37][38][39][40], and MW magnetometers [41,42]. As compared to traditional measurement, atom-based measurement is intrinsically calibrated where field strength is translated into Rabi frequency W via well-known atomic constants.…”