Normal tracing deflectometry using a secondary light source.

Area of Science:

• Optical Engineering
• Metrology
• Surface Science

Background:

• Traditional scanning deflectometric profilers using f-theta systems are standard for mirror profile measurements at synchrotron facilities.
• These conventional profilers rely on a pencil beam, which can be susceptible to systematic errors from manufacturing defects and optical aberrations.

Purpose of the Study:

• To develop an improved optical system for measuring surface profiles with enhanced accuracy.
• To minimize systematic errors inherent in traditional profilers, particularly those caused by optical element imperfections.

Main Methods:

• A novel system employing a secondary light source and a pinhole was designed to automatically select a beam.
• This selected beam propagates normally to the surface under test, enabling slope variation measurement by analyzing the beam's angular deviation.
• The developed method's performance was evaluated through simulations and compared against a conventional profiler method.

Main Results:

• The proposed method demonstrated the potential to significantly minimize systematic errors that affect traditional profilers.
• Simulation results indicate improved accuracy in measuring slope variations of the surface under test.
• Comparison with conventional methods suggests superior performance in mitigating errors from manufacturing defects and aberrations.

Conclusions:

• The developed optical system offers a promising alternative for high-accuracy surface profile metrology.
• This technique is particularly beneficial for applications requiring precise measurements, such as at synchrotron facilities.
• The method effectively reduces systematic errors, leading to more reliable mirror profile characterization.