Sensing pulses of radio frequency fields

A method comprising:

• passing beams of light through a vapor in a vapor cell sensor, the beams of light comprising a probe beam of light;
• allowing an RF field to interact with the vapor;
• generating, by operation of an optical detector, a detector signal that is based on the probe beam of light after the probe beam has passed through the vapor;
• receiving the detector signal at a signal processing system over a time period;
• and
• by operation of the signal processing system:
• generating a digital signal based on the detector signal, the digital signal representing a measured response of the vapor to the RF field over the time period,
• applying a matched filter to the digital signal to generate a filtered signal, the filtered signal generated based on a comparison of the digital signal with a response template, the response template representing a known response of the vapor to a target RF pulse, and
• processing the filtered signal to determine properties of the RF field experienced by the vapor over the time period.

A non-transitory computer-readable medium comprising instructions that are operable, when executed by a data processing apparatus, to perform operations that comprise:

• generating a digital signal that represents a measured response of a vapor to an RF field experienced by the vapor over a time period, the digital signal based on a detector signal from an optical detector over the time period, wherein:
• the vapor resides in a vapor cell sensor configured to allow beams of light to pass through the vapor, the beams of light comprising a probe beam of light, and
• the optical detector is configured to receive the probe beam of light after the probe beam has passed through the vapor, and in response, generate the detector signal;
• applying a matched filter to the digital signal to generate a filtered signal, the filtered signal generated based on a comparison of the digital signal with a response template, the response template representing a known response of the vapor to a target RF pulse;
• and
• processing the filtered signal to determine properties of the RF field experienced by the vapor over the time period.