Sensor system and method for analyzing a spectrum of an EM signal

A sensor system for analyzing a spectrum of an electromagnetic, EM, signal, comprising:

• a vapor cell containing at least one species of atoms in a gaseous form, wherein the atoms in the vapor cell are exposed to the EM signal;
• at least one excitation source configured to excite a number of atoms in the vapor cell to a Rydberg state, wherein at least a fraction of the excited atoms are ionized;
• a signal generator configured to generate a microwave signal with a spatially varying signal strength and/or frequency in the vapor cell;
• a number of electrode pairs which are arranged along the vapor cell, and which are configured to apply an electric field to the atoms in the vapor cell;
• a current sense circuit configured to detect a current between at least one of the number of electrode pairs, wherein the current is caused by ionized atoms in the vapor cell;
• and
• a processor configured to determine spectral information of the EM signal based on the detected current.

A method for analyzing a spectrum of an electromagnetic, EM, signal, comprising:

• exciting a number of atoms in a vapor cell containing at least one species of atoms in a gaseous form to a Rydberg state, wherein at least a fraction of the excited atoms are ionized;
• generating a spatially varying electric and/or magnetic field in the vapor cell;
• exposing the vapor cell to the EM signal;
• detecting a current between at least one of a number of electrode pairs which are arranged along the vapor cell, wherein the current is caused by ionized atoms in the vapor cell;
• and
• determining spectral information of the EM signal based on the detected current.