Abstract: In a general aspect, a quantum spectrum sensing network for detecting electromagnetic radiation in an environment is presented. In some implementations, a spectrum sensing network includes a computer system; and a plurality of portable systems spatially distributed over a geographic region. Each of the plurality of portable systems includes one or more vapor cell sensors each including a vapor and being configured to generate output optical signals based on interactions between input optical signals, the vapor and electromagnetic radiation; a portable control package including one or more processors configured to process the output optical signals; and a communication module configured to communicate, to the computer system, data based on the processed output optical signals.

Abstract: In a general aspect, a quantum spectrum sensing system is presented. In some implementations, a quantum spectrum sensing system includes a laser system, a vapor cell sensor, and an optical detector. The laser system includes first and second lasers configured to generate a first and second laser signals. The laser system also includes first and second comb generators configured to produce first and second frequency comb signals based on the first and second laser signals, respectively. The laser system includes a frequency separator that can select frequency components of the second frequency comb signal and a frequency shifter that can shift the selected frequency components toward Rydberg states of a vapor. The vapor cell sensor can receive input optical signals from the laser system and produce output optical signals based on interactions of the vapor with the input optical signals. The optical detector can detect the output optical signals.

Abstract: In a general aspect, a portable quantum spectrum sensing system for detecting electromagnetic radiation in an environment is presented. In some implementations, a portable system includes a vapor cell sensor and a portable control package. The vapor cell sensor includes a vapor and is configured to generate output optical signals based on interactions between input optical signals, the vapor and the electromagnetic radiation. The portable control package includes a laser system configured to generate laser signals and a photonic integrated circuit system configured to generate the input optical signals based on the laser signals from the laser system. The portable control package includes a system-on-chip that can communicate control signals to the laser system and the photonic integrated circuit system. The system-on-chip can also process the output optical signals to determine one or more properties of the electromagnetic radiation.

Abstract: In a general aspect, a quantum spectrum sensing system is presented. In some implementations, a system includes a laser system, a vapor cell sensor, an optical detector, and a signal processing system. The laser system includes a first laser that generates a first laser signal; a comb generator that produces a frequency comb signal based on the first laser signal; and a second laser generates a second laser signal. The vapor cell sensor includes a vapor and receives input optical signals based on the frequency comb signal and the second laser signal. The vapor cell sensor produces output optical signals based on interactions of the vapor with the input optical signals and electromagnetic radiation. The signal processing system processes the output optical signals to identifying signals in the electromagnetic radiation that are off resonance with a transition frequency between Rydberg states of the vapor.

Abstract: In a general aspect, a quantum spectrum sensing system is presented. In some implementations, a system includes a laser system, a vapor cell sensor, an optical detector, and a signal processing system. The laser system includes a first laser that generates a first laser signal; a comb generator that produces a frequency comb signal based on the first laser signal; and a second laser generates a second laser signal. The vapor cell sensor includes a vapor and receives input optical signals based on the frequency comb signal and the second laser signal. The vapor cell sensor produces output optical signals based on interactions of the vapor with the input optical signals and electromagnetic radiation. The signal processing system processes the output optical signals to identifying signals in the electromagnetic radiation that are off resonance with a transition frequency between Rydberg states of the vapor.

Abstract: In a general aspect, a quantum spectrum sensing system is presented. In some implementations, a quantum spectrum sensing system includes a laser system, a vapor cell sensor, and an optical detector. The laser system includes first and second lasers configured to generate a first and second laser signals. The laser system also includes first and second comb generators configured to produce first and second frequency comb signals based on the first and second laser signals, respectively. The laser system includes a frequency separator that can select frequency components of the second frequency comb signal and a frequency shifter that can shift the selected frequency components toward Rydberg states of a vapor. The vapor cell sensor can receive input optical signals from the laser system and produce output optical signals based on interactions of the vapor with the input optical signals. The optical detector can detect the output optical signals.

Abstract: In a general aspect, vapor cell sensors are used to perform over-the-air (OTA) testing of cellular base stations. In some implementations, a vapor cell sensor including a vapor having Rydberg states is tuned to a carrier frequency of RF radiation emitted from a cellular base station. A first set of optical signals is generated based on an interaction between the vapor and a synchronization signal transmitted from the cellular base station. The vapor cell sensor is tuned to a harmonic of the carrier frequency. A second set of optical signals is generated based on an interaction between the vapor and the RF radiation. The first and second sets of optical signals are converted to digital data. The digital data is processed to detect a condition of the cellular base station.

Abstract: In a general aspect, vapor cell sensors are used to perform OTA testing of cellular base stations. In some implementations, a system for performing OTA testing of a cellular base station includes a vapor cell sensor including a vapor having Rydberg states and a control system communicably coupled to the vapor cell sensor and configured to tune the vapor cell sensor to a carrier frequency of RF radiation emitted from the cellular base station; receive a first set of optical signals generated based on an interaction between the vapor and a synchronization signal; tune the vapor cell sensor to a harmonic of the carrier frequency; receive a second set of optical signals generated by the vapor cell based on an interaction between the vapor and the RF radiation; convert the first and second sets of optical signals to digital data; and process the digital data to detect a condition of the cellular base station.

Abstract: In a general aspect, vapor cell sensors are used to perform over-the-air (OTA) testing of cellular base stations. In some implementations, a vapor cell sensor including a vapor having Rydberg states is tuned to a carrier frequency of RF radiation emitted from a cellular base station. A first set of optical signals is generated based on an interaction between the vapor and a synchronization signal transmitted from the cellular base station. The vapor cell sensor is tuned to a harmonic of the carrier frequency. A second set of optical signals is generated based on an interaction between the vapor and the RF radiation. The first and second sets of optical signals are converted to digital data. The digital data is processed to detect a condition of the cellular base station.