Carrier optical vortex interferometer using segmentation demodulation method for dynamic measurement of axisymmetric...

Area of Science:

• Optics and Photonics
• Nanotechnology
• Mechanical Engineering

Background:

• Dynamic measurement of nanoscale surface deformation is crucial for micromechanical and thermophysical research.
• Existing methods may lack the precision or dynamic range required for certain applications.

Purpose of the Study:

• To introduce a new interferometric technique for dynamic measurement of axisymmetric surface deformation.
• To demonstrate the capability of the proposed method for high-precision, real-time deformation analysis.

Main Methods:

• Utilizing a carrier optical vortex interferometer (COVI) with coaxial superposition of Laguerre-Gaussian beams.
• Employing a rotating chopper to introduce carrier frequency and a multi-ring segmentation detection scheme.
• Analyzing Doppler shifts to determine surface deformation velocities and integrating them to obtain the deformation profile.

Main Results:

• The COVI successfully measured external force-induced axisymmetric surface deformation dynamically.
• Measurement error for surface deformation velocity was within (-2.1, 1.1 nm/s) for velocities of 20-86 nm/s.
• The system achieved a lower measurable velocity limit of 20 nm/s and a surface deformation profile error of less than 2.5 nm.

Conclusions:

• The carrier optical vortex interferometer (COVI) provides a viable method for dynamic nanoscale surface deformation measurement.
• The technique offers high precision and sensitivity, with potential applications in various scientific and engineering fields.