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Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies
Published on: December 18, 2015
Heterodyne wavelength meter for continuous-wave lasers.
Xin Wang1, Yan Li, Shulian Zhang
1Department of Precision Instruments and Mechanology, Tsinghua University, Beijing, China. xin-wang@mails.tsinghua.edu.cn
Applied Optics
|August 19, 2007
Summary
This study introduces a novel heterodyne interferometer wavelength meter. It accurately measures laser wavelengths by comparing phase shifts, even for unstable or low-intensity light sources.
Area of Science:
- Optics and Photonics
- Interferometry
- Laser Metrology
Background:
- Accurate wavelength measurement is crucial for various scientific and industrial applications.
- Traditional methods can be limited by light source stability and intensity.
- Heterodyne interferometry offers a robust approach to phase measurement.
Purpose of the Study:
- To develop and demonstrate a novel wavelength meter utilizing heterodyne interferometry.
- To overcome limitations of existing wavelength measurement techniques regarding light source stability and intensity.
- To achieve high accuracy in wavelength determination for tunable diode lasers.
Main Methods:
- A heterodyne interferometer was designed and constructed.
- Acousto-optic modulators were used to create two orthogonal, frequency-shifted polarized components from a test laser.
- The modulated laser beam and a two-wavelength laser beam were analyzed in a common path.
- The ratio of interference phase shifts was measured to determine the wavelength ratio.
Main Results:
- The heterodyne technique successfully measured interference phase shifts, independent of intensity fluctuations.
- The system demonstrated the ability to measure low-intensity light sources.
- A tunable diode laser within the 630-637 nm range was measured with an accuracy of 5 parts in 10^7.
- The developed wavelength meter is robust against environmental disturbances.
Conclusions:
- The presented heterodyne interferometer wavelength meter offers a highly accurate and stable method for wavelength measurement.
- The technique is suitable for a wide range of light sources, including those with unstable or low intensity.
- This technology has potential applications in spectroscopy, optical communications, and precision metrology.
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