- Atomic clocks are the backbone of the Global Positioning System (GPS), crucial for navigating cities, responding to emergencies, and organizing military operations.
- Both atomic and optical atomic clocks are sophisticated yet bulky, power-hungry, fragile, and expensive, limiting their use to large research facilities.
- Strontium (Sr) and ytterbium ions are commonly used in Optimal Atomic clocks. Indian researchers are developing such clocks to enhance precision timekeeping in India.
Atomic Clocks
- Atomic clocks use atoms to keep time. A popular design employs caesium-133 (Cs-133) atoms, first used in 1967 to define the second. Cs-133 is highly stable and naturally occurring.
- Atomic clocks exploit the atom’s ability to jump between energy levels, with Cs-133 absorbing microwave radiation at 9,192,631,770 Hz to measure one second.
- The feedback mechanism maintains accuracy, with caesium atomic clocks losing or gaining a second every 1.4 million years.
- A study in Nature introduced a portable optical atomic clock for use onboard ships, trading some accuracy for size and robustness, but still outperforming other vessel-borne timekeeping options.
- Portable Optimal Atomic Clock:
- The study developed a portable optical atomic clock using molecular iodine as the frequency standard.
- Researchers miniaturized the clock’s components.
Principle of Atomic Clock
An atomic clock operates like a conventional clock but uses the precise frequency of atoms transitioning between energy states as its time base. When an atom is excited by an external energy source, it moves to a higher energy state and then returns to a lower state, emitting energy at a specific frequency characteristic of that atom, which is detected and used as an input to a counter, ensuring highly accurate timekeeping.
- Initial tests at the U.S. National Institute of Standards and Technology (NIST) showed these clocks outperformed traditional hydrogen and rubidium atomic clocks in accuracy and stability.
Dig Deeper: Which type of atomic clock is used in the NavIC system?
