Why in the News?
- Frequency combs are highlighted as key modern tools used in atomic clock calibration and other precision measurements.
What is a Frequency Comb
- A special type of laser light
- Its spectrum looks like the teeth of a comb
- Connects the radio frequency domain (below ~100 GHz) with the optical domain (above ~200 THz)
- Acts as a precise bridge between microwave and optical frequencies
Key Characteristics
- Emits many evenly spaced frequencies, not a single colour
- Frequency spacing is extremely regular
- Exhibits very high stability and precision
- Enables coherent phase connection across wide frequency ranges
- Compact and highly reliable measurement tool
Why It Is Important
- Allows comparison of an unknown light frequency with a stable reference
- Achieves extraordinary measurement accuracy
- Revolutionised precision metrology and optical physics
Applications of Frequency Combs
- Calibration of atomic clocks
- Measurement of gravitational redshift effects on light
- Detection of exoplanets using precise stellar spectroscopy
- High speed and ultra precise spectroscopy
- Fundamental physics experiments and precision navigation
Prelims Takeaway
- Frequency comb equals laser with evenly spaced frequencies
- Acts as a frequency ruler for light
- Essential for atomic clocks, astrophysics, spectroscopy, and precision measurements
| The term ‘Goldilocks Zone’ is often seen in the news in the context of (2015)
(a) the limits of habitable zone above the surface of the Earth (b) regions inside the Earth where shale gas is available (c) search for the Earth-like planets in outer space (d) search for meteorites containing precious metals |
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