Laser Excited Atoms Detect Entire Radio-Frequency
United States Army Research Labs have developed a sensor that can detect the entire Radio Frequency (RF) spectrum at room temperature. At the heart of this technology lies a Rydberg atom, which is an atom whose electrons have a very high quantum number n , which describes the energy level of the electron, meaning they are far away from the nucleus of the atom. Their position in the atom causes them to have an exaggerated response to electric and magnetic fields making them ideal for communication receivers or detection devices . The Rydberg atom is placed directly above a microwave plane guide that enhances the incoming portion of the spectrum. Due to the sensitivity of the atoms to the changing voltage, the atom is capable of detecting the entire RF spectrum continuously.
Article: Rydberg Atoms Detect Radio-Frequency Spectrum