A research team from the National Time Service Center (NTSC) of the Chinese Academy of Sciences (CAS) has proposed novel schemes for coherent population trapping (CPT) resonance, which will help to implement compact and high-performance CPT atomic clocks.
CPT atomic clocks can provide crucial technical supports for deep space exploration, micro/nano satellite, high-speed communication, underwater resource exploration and other applications that require high-precision time but constrained on size, weight, and power consumption.
Current chip-scale atomic clock (CSAC) products are all based on CPT resonance with microwave free and simple structure.
"However, the performance of frequency stability of current CSAC is around 3E-10@1s," said Prof. YUN Enxue from NTSC, leader of this research team.
In order to improve the frequency stability of the CPT atomic clock while maintain its compactness, the researchers proposed and demonstrated novel CPT configurations, in which electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA) were observed simultaneously. A differential CPT signal was also obtained by subtraction of EIT and EIA signals.
"CPT resonances with doubled amplitude and suppressed common-mode noise are observed," said Prof. YUN. "The CPT schemes with enhanced signal-to-noise ratio of CPT signals will help to implement high-performance CPT atomic clocks, atomic sensors, precision spectroscopy, etc."
