Optimization strategies for suppressing instrumentation drift effects in measurements

Area of Science:

• Metrology
• Optical Engineering
• Instrumentation

Background:

• Environmental factors like temperature fluctuations cause drift, degrading measurement accuracy in precision instruments.
• Traditional methods for drift suppression in surface profilers, such as forward-backward scanning, are inefficient and ineffective against nonlinear drift.

Purpose of the Study:

• To develop a novel measurement strategy for suppressing low-frequency environmental drift in long-range surface profiler measurements.
• To improve measurement efficiency and accuracy by transforming drift characteristics rather than relying on averaging.

Main Methods:

• A new approach inspired by lock-in amplifiers (LIA) to shift drift frequencies into a filterable range.
• Implementation of optimized forward-backward downsampled path scanning and random sampling strategies.
• Multi-objective optimization to determine optimal sampling parameters for balancing accuracy and efficiency in long-trace profiler (LTP) systems.

Main Results:

• Simulations demonstrated that optimized path scanning effectively suppresses both linear and nonlinear drift, outperforming traditional and random methods.
• Experimental validation showed an 18 nrad RMS drift error and a 48.4% reduction in measurement time compared to conventional scanning.
• The proposed method significantly enhances system robustness by reducing reliance on stringent environmental controls.

Conclusions:

• Optimized downsampled path scanning offers a robust and efficient solution for high-precision optical surface metrology.
• This technique alleviates the need for extensive environmental stabilization, enabling direct measurements.
• The findings present a new paradigm for drift suppression in sensitive metrology applications.