Related Experiment Video
Updated: May 16, 2026
08:23
A Random-displacement Measurement by Combining a Magnetic Scale and Two Fiber Bragg Gratings
Published on: September 30, 2019
Real-time displacement measurement immune from atmospheric parameters using optical frequency combs
Pu Jian1, Olivier Pinel, Claude Fabre
1Laboratoire Kastler Brossel, Université Pierre et Marie Curie-Paris 6, ENS, CNRS, Paris, France.
Optics Express
|November 29, 2012
Summary
This study introduces a novel optical frequency comb method for precise, real-time distance measurement in air. It optically corrects for atmospheric changes, overcoming dispersion limitations for long-distance applications.
Area of Science:
- Optics and Photonics
- Metrology
- Atmospheric Science
Background:
- Dispersion in air limits precision in long-distance optical measurements.
- Environmental factors like temperature and humidity cause refractive index variations, affecting accuracy.
- Existing methods struggle with real-time compensation for these atmospheric fluctuations.
Purpose of the Study:
- To develop a direct and real-time displacement measurement technique.
- To optically compensate for atmospheric index of refraction variations.
- To enable high-precision measurements over long distances in air.
Main Methods:
- Utilizing an optical frequency comb as a precise source.
- Employing multi-wavelength interferometry within a homodyne detection scheme.
- Temporally shaping the local oscillator signal.
Main Results:
- Achieved direct and real-time displacement measurement.
- Successfully compensated for atmospheric parameter-induced refractive index variations.
- Demonstrated insensitivity to environmental fluctuations (pressure, temperature, humidity, CO2).
Conclusions:
- The proposed method offers a robust solution for precise long-distance metrology in air.
- Optical compensation for atmospheric dispersion is key to overcoming current limitations.
- This technique is suitable for applications demanding stringent precision despite environmental variability.
Related Concept Videos
01:30Electronic Distance Measuring Instruments
Electronic Distance Measuring Instruments (EDMs) are essential tools in modern surveying, offering precise distance measurements by emitting electromagnetic signals and calculating the time required for these signals to travel to a target and return. Two primary types of signals are used in EDMs — light waves and microwaves — each suited to specific environmental and distance requirements. Light-wave-based EDMs utilize either infrared or laser light, providing high accuracy over short distances...
01:05Doppler Effect - II
The Doppler effect has several practical, real-world applications. For instance, meteorologists use Doppler radars to interpret weather events based on the Doppler effect. Typically, a transmitter emits radio waves at a specific frequency toward the sky from a weather station. The radio waves bounce off the clouds and precipitation and travel back to the weather station. The radio frequency of the waves reflected back to the station appears to decrease if the clouds or precipitation are moving...