Related Experiment Video
Updated: May 22, 2026
16:11
Implementation of a Reference Interferometer for Nanodetection
Published on: April 26, 2014
Wind speed measurements of Doppler-shifted absorption lines using two-beam interferometry
Robert M Pierce1, Shane E Roark
1Ball Aerospace & Technologies Corporation, Boulder, Colorado 80306-1062, USA. rpierce@ball.com
Applied Optics
|April 27, 2012
Summary
This study introduces two-beam interferometry for measuring wind speed using Doppler-shifted absorption lines. The developed system achieved a 5 m/s precision, though filter instability limited its full potential.
Area of Science:
- Atmospheric physics
- Optical remote sensing
- Interferometry
Background:
- Remote wind speed measurement often uses Doppler-shifted optical spectra.
- Active and passive systems exist, but two-beam interferometry of absorption lines is novel.
- Challenges include precise line shape knowledge, stable filtering, and interferometer response.
Purpose of the Study:
- To investigate two-beam interferometry for measuring wind speed via Doppler-shifted absorption lines.
- To design and implement a Michelson interferometer system for this purpose.
- To analyze technical hurdles and optimize instrument design.
Main Methods:
- Utilized a Michelson interferometer combined with a Fabry-Perot filter.
- Analyzed the optimal optical path difference for given spectra and filters.
- Measured Doppler shifts of oxygen absorption lines.
Main Results:
- Achieved a wind speed measurement precision of 5 m/s.
- Theoretical shot-noise limit was below 1 m/s.
- Residual filter instability was identified as the primary resolution limitation.
Conclusions:
- Two-beam absorption line interferometry is a viable, though challenging, method for remote wind sensing.
- Instrument design and precise filtering are critical for accurate measurements.
- Further improvements are needed to overcome limitations for broader application.
Related Concept Videos
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...
00:56Doppler Effect - I
The Doppler effect and Doppler shift were named after the Austrian physicist and mathematician Christian Johann Doppler in 1842, who conducted experiments with both moving sources and moving observers. Consider an observer standing on a street corner, observing an ambulance with a siren sound passing by at a constant speed. The observer experiences two characteristic changes in the sound of the siren. Initially, the sound increases in loudness as the ambulance approaches and decreases in...
01:25Atomic Absorption Spectroscopy: Interference
Interference leads to systematic error in atomic absorption (AA) measurements by enhancing or diminishing the analytical signal or the background. These interferences can be grouped into three main categories: spectral interference, chemical interference, and physical interference.
Spectral interference occurs when signals from other elements or molecules overlap with the analyte signal, falsely elevating or masking the analyte's absorbance. This interference can be corrected using Zeeman,...
Spectral interference occurs when signals from other elements or molecules overlap with the analyte signal, falsely elevating or masking the analyte's absorbance. This interference can be corrected using Zeeman,...
01:30Atomic Emission Spectroscopy: Interference
In atomic emission spectroscopy (AES), high-temperature atomizers excite a broad range of elements and molecules that generate complex emissions from sources such as oxides, hydroxides, and flame combustion products in the flame or plasma. Several strategies can be employed to minimize spectral interferences caused by overlapping emission lines or bands. These include increasing instrument resolution, choosing alternative emission lines, optimally placing the detector in low-background regions,...
02:18Interference and Diffraction
Interference is a characteristic phenomenon exhibited by waves. When two electromagnetic waves interact with their peaks and troughs coinciding, a resulting wave with enhanced amplitude is produced. This is known as constructive interference. In this case, the two waves interacting are in phase with each other.
01:22Atomic Emission Spectroscopy: Instrumentation
The instrumentation of atomic emission spectrometry (AES) involves various components, including atomization devices that convert samples into gas-phase atoms and ions. There are two main types of atomization devices: continuous and discrete atomizers. Continuous atomizers, like plasmas and flames, introduce samples in a constant stream, while discrete atomizers inject individual samples using syringes or autosamplers. The most common discrete atomizer is the electrothermal atomizer.