Environmental influences on autocollimator-based angle and form metrology.

Area of Science:

• Optical metrology
• Precision engineering
• Environmental sensing

Background:

• Deflectometric profilometers are essential for measuring the form of beam-shaping optics in synchrotrons and X-ray Free Electron Lasers.
• These instruments rely on commercial autocollimators for contactless slope measurement, crucial for achieving high accuracy in modern X-ray optics.

Purpose of the Study:

• To investigate the impact of environmental parameters, including temperature and air pressure gradients, on high-accuracy metrology using autocollimators.
• To identify and quantify systematic errors introduced by environmental factors in deflectometric profilometry.
• To develop strategies for correcting these environmental influences and minimizing measurement errors.

Main Methods:

• Conducted extensive theoretical and experimental investigations to characterize environmental influences on autocollimator-based slope measurements.
• Analyzed the effects of temperature and air pressure variations on form measurement accuracy, particularly for large and curved optical surfaces.
• Explored sophisticated experimental arrangements and methods to mitigate error contributions.

Main Results:

• Environmental parameters, especially gradients, can cause substantial systematic errors in form measurement.
• Relative angle and form measurement errors of the order of 10^-4 are predictable due to environmental influences.
• Quantified the impact of environmental factors on the precision of deflectometric profilometers.

Conclusions:

• Strategies for correcting environmental influences have been derived, enabling more accurate form measurements.
• Minimizing environmental contributions through advanced experimental designs is feasible.
• This work advances the understanding of fundamental limits in autocollimator-based slope and form metrology.