ATOMIC CLOCKS - SCI
& TECH
News: New portable atomic clock offers very accurate timekeeping at sea
What's in the news?
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A recent study published in Nature introduced a
portable optical atomic clock using molecular
iodine as the frequency standard that can be used onboard ships.
Atomic Clocks:
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An atomic clock is a highly precise timekeeping
instrument that utilises the natural
vibrations of atoms to measure time.
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This device leverages the constant frequency of
atoms to ensure more stable
timekeeping compared to traditional quartz clocks.
Backdrop:
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It was invented in 1955 by Louise Essen.
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Currently, only four countries, the United States, the
United Kingdom, Japan, and South Korea have developed their atomic clocks.
Types of Atomic Clocks:
1. Traditional Atomic
Clocks:
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These utilise atoms such as caesium (Cs-133) to measure time, defining one second as
9,192,631,770 oscillations of the caesium atom.
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Cesium atomic clocks are highly precise and form the primary
standard for the second in the International System of Units (SI).
2. Rubidium Atomic
Clocks:
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Similar to caesium clocks, rubidium atomic clocks
use rubidium atoms for time measurement.
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They are typically smaller, less expensive, and more portable, making them ideal for
situations where space and cost are considerations.
3. Hydrogen Maser
Clocks:
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Offering even greater
precision than cesium clocks, hydrogen maser clocks utilise the hyperfine
transition of hydrogen atoms.
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These clocks operate at higher frequencies, providing exceptional short-term stability and
accuracy.
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They are frequently used in scientific research,
satellite navigation, and space missions.
2. Optical Atomic
Clocks:
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These use atoms like strontium or ytterbium, operating at optical frequencies for higher accuracy.
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They use lasers to stimulate atomic transitions.
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They are poised for future applications in
fundamental physics research and advanced systems.
Working of Traditional
Atomic Clocks:
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Atomic Transitions - Atomic clocks utilise the
fundamental property of atoms to jump between different energy levels. These
jumps are like steps on a ladder, with atoms absorbing energy, such as
electromagnetic radiation, to climb up.
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Resonance - The frequency of microwave radiation applied to
Cs atoms in a cavity is adjusted until it matches the transition energy, a
phenomenon called resonance.
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Feedback - A feedback mechanism ensures the accuracy of
atomic clocks by detecting and adjusting any changes in resonance frequency.
Working of Optical
Atomic Clocks:
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Lasers and Coherence - Optical atomic clocks use
lasers to stimulate atomic transitions. These lasers emit highly coherent
light, meaning all light waves have the same frequency and a consistent
relationship between their wavelengths. This results in light with precise properties
and stability.
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Two Factors for Accuracy - The higher operating
frequency and narrower line widths of optical atomic clocks contribute to their
enhanced accuracy.
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Higher operating frequency means more oscillations
within a given time frame, allowing for the measurement of smaller increments
of time.
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Narrower line widths, referring to the frequency
range over which transitions occur, facilitate precise tuning of the optical
light frequency, leading to higher accuracy.
Atomic Clocks in India:
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India aims
to deploy its own atomic clocks across the nation, to enhance its
timekeeping infrastructure and national defence capabilities for the future.
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Currently, India relies on foreign atomic clocks, particularly those in the
US.
Rationale Behind Atomic
Clocks Development:
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The initiative was started due to the denial of
Global Positioning System (GPS) information during the Kargil War in 1999.
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The existence of independent timekeeping
capabilities is crucial for defence, cybersecurity, and online transactions.
Development of
Indigenous Atomic Clocks in India:
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India is advancing its development of atomic clocks
to decrease dependence on foreign technology, particularly for crucial systems
like the Indian Regional Navigation Satellite System (IRNSS), also known as NavIC.
Autonomy and Security
Benefits:
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By developing its own atomic clocks, India seeks to
maintain full control over its navigation systems.
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This autonomy is critical for national security and
promotes technological independence, enhancing the country's ability to manage
and secure its own infrastructure.