Electrometer with radio frequency (RF) tuning waveguide

A method for detecting an external signal via an electrometer system, the method comprising:

• providing a probe beam through a sensor cell comprising alkali metal atoms, the probe beam exiting the sensor cell as a detection beam;
• providing a coupling beam through the sensor cell to excite the alkali metal atoms from a ground state to a Rydberg energy state of the alkali metal atoms based on the probe beam and the coupling beam;
• providing a radio frequency (RF) tuning signal through the sensor cell via a waveguide that extends within the sensor cell and along a length of the sensor cell from a first end of the sensor cell through the sensor cell to a second end of the sensor cell opposite the first end to tune at least one energy state of the alkali metal atoms relative to the Rydberg energy state;
• and
• monitoring the detection beam to detect the external signal.

An electrometer system comprising:

• a sensor cell comprising alkali metal atoms within;
• a probe laser configured to generate a probe beam directed through the sensor cell in a first direction, the probe beam exiting the sensor cell as a detection beam;
• a coupling laser configured to generate a coupling beam directed through the sensor cell collinearly and anti-parallel with the probe beam to provide a first Rydberg energy state of the alkali metal atoms;
• a signal generator configured to generate a radio frequency (RF) tuning signal;
• a waveguide extending within the sensor cell from a first end of the sensor cell through the sensor cell to a second end of the sensor cell opposite the first end, the waveguide being configured to propagate the RF tuning signal in the sensor cell to tune the alkali metal atoms to a second Rydberg energy state;
• and
• a detection system configured to monitor the detection beam to detect an external signal based on monitoring the detection beam.