Long distance measurement using optical sampling by cavity tuning.

Area of Science:

• Metrology
• Optical Physics
• Precision Engineering

Background:

• Accurate absolute distance measurement is crucial for various scientific and industrial applications.
• Traditional interferometric methods can be complex and sensitive to environmental disturbances.

Purpose of the Study:

• To demonstrate a novel method for absolute distance measurement using optical sampling by cavity tuning.
• To achieve high-precision length determination with improved stability and reduced complexity.

Main Methods:

• Employing optical sampling by cavity tuning to generate cross-correlation patterns.
• Utilizing a frequency comb with a swept repetition frequency.
• Actively stabilizing a 114 m fiber delay line with a feedback servo loop to 10⁻¹⁰ stability.

Main Results:

• Successfully measured unknown distances by identifying the instantaneous repetition frequency at the fringe packet peak.
• Compared the novel technique with a reference incremental interferometer.
• Achieved agreement within 3 μm over a 60 m distance, corresponding to a relative accuracy of 10⁻⁸.

Conclusions:

• The demonstrated optical sampling method provides a robust and accurate approach for absolute distance measurement.
• This technique offers a competitive alternative to existing interferometric methods, particularly for long distances.
• The high stability and accuracy pave the way for advanced metrology applications.