Securing noise-adaptive selection of interference signal by nonlinear detection

Area of Science:

• Optics and Photonics
• Interferometry
• Nonlinear Optics

Background:

• Interferometers typically use linear detection for interference fringe signals.
• Modulating signals to specific frequency regions is standard practice.
• Nonlinear detectors offer a new approach to analyzing interference fringes.

Purpose of the Study:

• To analyze the formation of nonlinearly detected interference fringes.
• To demonstrate the use of high-harmonic interference fringes for precise measurements.
• To introduce a noise-adaptive method for optical measurements.

Main Methods:

• Analysis of nonlinear detection in interferometers.
• Utilizing high-harmonic waves generated by nonlinear detectors.
• Matching peak envelopes of fundamental and high-harmonic interference fringes.
• Experimental verification of the proposed technique.

Main Results:

• Nonlinear detectors produce interference fringes for fundamental and high-harmonic waves.
• High-harmonic interference fringes can determine zero optical path length difference.
• Peak envelopes of fundamental and high-harmonic fringes align at zero optical path length, ensuring noise-adaptive selectability.
• The method was successfully verified with experimental data.

Conclusions:

• The proposed method enables accurate determination of zero optical path length difference using high-harmonic interference fringes.
• This technique offers enhanced noise adaptivity in interferometric measurements.
• The method is applicable to surface profiling and length measurements.