NIST researchers have demonstrated a new method for transmitting precise time signals through the atmosphere with femtosecond accuracy, potentially enabling synchronization of optical atomic clocks separated by continents. The technique, using a time programmable frequency comb, could allow future geosynchronous satellite links to maintain high precision timing with minimal signal strength, making it robust against atmospheric disturbances.
The experiment, conducted between two mountains in Hawaii, demonstrated that the system could operate at the quantum limit – sending only 40 microwatts of power and receiving less than one photon in a billion. This breakthrough could support the redefinition of the SI second to an optical standard and enable distributed sensing applications like very long baseline interferometry for black hole imaging.
The NIST team is now working to reduce the system’s size, weight, and power requirements, and adapt it for use with moving platforms. The research, published in Nature, could have significant implications for future quantum technologies and fundamental physics measurements.
Keywords: optical, quantum, femtosecond, precision, synchronization
