Digital correction method for realizing a phase-stable dual-comb interferometer.

Area of Science:

• Optical Metrology
• Interferometry
• Materials Science

Background:

• Phase-stable dual-comb interferometers are crucial for measuring broadband optical response functions.
• Traditional methods rely on complex tight phase-locking techniques.
• Carrier wave phase noise and interferogram timing jitter limit measurement accuracy.

Purpose of the Study:

• To present a novel post-correction algorithm for stabilizing dual-comb interferometers.
• To compensate for phase noise and timing jitter without active phase-locking.
• To enhance the precision of optical metrology measurements.

Main Methods:

• Development of a post-correction algorithm.
• Utilizing a beat signal between two optical frequency combs.
• Employing a free-running continuous wave laser as an optical intermediary for signal generation.
• Experimental validation of the algorithm's performance.

Main Results:

• Demonstrated compensation for carrier wave phase noise.
• Achieved compensation for interferogram timing jitter.
• Experimental results show sub-hertz relative linewidth.
• Demonstrated ~1 ns relative timing jitter and 0.2 rad precision in carrier phase.

Conclusions:

• The post-correction algorithm effectively stabilizes dual-comb interferometers.
• This method offers a simpler alternative to traditional phase-locking techniques.
• The demonstrated precision significantly advances optical metrology capabilities for materials characterization.