Quantum electromagnetic field sensor

Inventors

Moore, Kaitlin • McBride, Sterling Eduardo • Chan, Winston K. • Braun, Alan M. • Gentry, Cale M.

Assignees

SRI International Inc

Abstract

In one example, a sensor comprising a vapor cell including a vapor of alkali atoms is disclosed. The sensor further comprises a system configured to direct electromagnetic (EM) radiation of one or more frequencies into the vapor cell and incident on the vapor of alkali atoms. The EM radiation of one or more frequencies is configured to prepare the alkali atoms from a first quantum state to a Rydberg state. The alkali atoms prepared in the Rydberg state comprise an orbital angular momentum quantum number that is at least the number of quanta of the one or more frequencies. The sensor further comprises a detector configured to detect a response of the alkali atoms to incident electromagnetic radiation after the alkali atoms are prepared in the Rydberg state.

Core Innovation

The electromagnetic sensor uses a vapor cell containing alkali atoms prepared to Rydberg states, where the prepared Rydberg states have an orbital angular momentum quantum number that is at least a number of quanta of one or more frequencies. The alkali atoms are transitioned from a first quantum state to the Rydberg state via at least two intermediary quantum states, and the sensor detects a response of the alkali atoms in the Rydberg state to incident EM radiation and generates an output signal proportional to the detected response.

The disclosed excitation is performed using multi-frequency excitation that includes intermediary quantum states between the first quantum state and the Rydberg state, including all-optical and mixed optical-RF paths. The description also discusses Doppler-free excitation and Stark tuning for resonance scanning across MHz–THz, and links the Rydberg-state orbital angular momentum to the number of frequency quanta used in the transition.

Detection modalities described for the sensor include electromagnetic induced transparency transmission changes, selective ionization with a corresponding current change in an electrical circuit, and fluorescence detection. The document also describes system architectures with optical probing, electronic and fluorescence detection schemes, and sensor hardware components such as vapor-cell windows, optical elements, RF waveguides, metasurfaces, and sensor arrays.

Claims Coverage

The independent claims cover a method and a vapor-cell sensor system configured to transition alkali atoms to a Rydberg state through intermediary quantum states and then detect the Rydberg-state response, with inventive features including multi-intermediary-state transitions and Rydberg-state orbital angular momentum tied to frequency quanta. A further independent claim specifies multiple optical element sets for visible/NIR and RF-range radiations.

Overall claim coverage centers on transitioning alkali atoms in a vapor cell from a first quantum state to a Rydberg state through at least two intermediary quantum states whose energies lie between the first and Rydberg states, requiring a Rydberg-state orbital angular momentum quantum number that is at least the number of frequency quanta. The claims then detect the Rydberg-state response to incident EM radiation, with one claim specifying multiple optical-element sets to deliver different visible/NIR and GHz–THz and MHz–GHz EM radiations.

Stated Advantages

Documented Applications