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Rydberg Atom Mixer and Determining Phase of Modulated Carrier Radiation

Patent Number: 10,979,147


A Rydberg atom mixer determines a phase of modulated carrier radiation and includes: a reference radiofrequency source for reference radiofrequency radiation; a modulated carrier source for modulated carrier radiation; a vapor cell to contain gas atoms and that receives reference radiofrequency radiation and modulated carrier radiation, such that the gas atoms produce modulated light modulated; and a transmission detector that receives the modulated light from the vapor cell and produces a transmission signal from the transmission detector for determination of a phase of the modulated carrier radiation, wherein the Rydberg atom mixer mixes the reference radiofrequency radiation and the modulated carrier radiation by the gas atoms in a Rydberg electronic state to produce the intermediate frequency IF that corresponds directly to the phase of the modulated carrier radiation.

Patent Description

Rydberg atoms have been shown to be very useful in performing absolute measurements of the magnitude of a radio frequency (RF) field using electromagnetically induced transparency (EIT). However, until this invention, there has been less success in using Rydberg atoms for the measurement of the phase of an RF field. Measuring the phase of a RF field is a necessary component for many important applications, including communications, antenna metrology, and radar. We invented a way to coherently mix and demodulate RF fields by using Rydberg atoms as a mixer where two input signals ( i.e., Local Oscillator (LO)and RF Signal) coherently create a third intermediate signal through the use of electromagnetically induced transparency and Autler-Towns splitting. The phase of the intermediate frequency (IF) corresponds directly to the phase of the RF field. Up until now only RF field amplitude could be measured using Rydberg atoms. See figure 1 below.

Block diagram of the Rydberg atom "mixer". The Rydberg atoms separate the difference frequency (IF) from two RF signals (LO and SIG). This demodulated signal is carried in the probe laser.


This invention allows for the first time coherent measurement of RF field phase using Rydberg atoms. This invention also increases the sensitivity of Rydberg atoms to RF fields beyond what can be detected using Autler-Townes splitting in EIT alone.

Created August 11, 2021, Updated April 11, 2024