Sideband analysis and seismic detection in a large ring laser.

Area of Science:

• Geophysics
• Optical Physics
• Seismology

Background:

• Ring lasers exploit the Sagnac effect for precise measurements.
• Earth's rotation induces a spectral line in ring laser output.
• Mechanical motions, like seismic events, can modulate this spectral line.

Purpose of the Study:

• To theoretically and experimentally investigate the sideband structure of Earth rotation-induced spectral lines.
• To establish the relative sideband height as a measure of rotational amplitude.
• To analyze seismic event data using this ring laser technique.

Main Methods:

• Utilizing a ring laser system sensitive to the Earth's Sagnac effect.
• Frequency modulation analysis of the induced spectral line in the microhertz-hertz region.
• Theoretical modeling and experimental validation of sideband structures.

Main Results:

• Achieved a frequency resolution of 1 part in 3 × 10(21).
• Demonstrated a rotational resolution of 300 microradians.
• Established relative sideband height as an absolute measure of rotational amplitude.

Conclusions:

• Ring laser technology offers unprecedented resolution for measuring Earth's rotation.
• Sideband analysis provides a novel method for quantifying seismic event amplitudes.
• The technique was successfully applied to analyze a specific seismic event.