Coherent microwave emission without population inversion: a new atomic frequency standard

The description of a new type of frequency standard based on coherent population trapping (CPT) in cesium is given. The phenomenon creates a magnetization oscillating at the hyperfine frequency. Microwave radiation emitted by such a magnetization is detected by means of a microwave cavity. The process takes place without population inversion. Results are given for continuous and pulsed operation. The possibility of using the CPT coherent microwave emission as the basis of a frequency standard is analyzed.