Defocused speckle imaging using digital image correlation for lensless tip and tilt measurements with experimental...

Area of Science:

• Optical Metrology
• Instrumentation Engineering

Background:

• Traditional autocollimators are widely used for angular measurements but can be expensive and have limitations in angular range.
• There is a need for cost-effective and versatile angular measurement solutions in scientific and industrial applications.

Purpose of the Study:

• To introduce and evaluate a novel optical instrument for angular measurements.
• To demonstrate the instrument's performance in terms of uncertainty and repeatability.
• To highlight its cost-effectiveness and wider angular range compared to traditional methods.

Main Methods:

• The instrument utilizes a defocused speckle pattern projected onto a sample.
• Angular orientation is determined by analyzing the captured reflected speckle pattern using a camera.
• System design, operational principles, and performance were rigorously evaluated.

Main Results:

• The developed instrument achieves an uncertainty level of 0.4 µrad and repeatability of 0.47 µrad.
• It demonstrates performance modestly comparable to traditional autocollimators.
• A significant advantage in angular range was observed compared to conventional systems.

Conclusions:

• The defocused speckle pattern instrument is a viable, cost-efficient alternative for angular measurements.
• Its performance and wider angular range make it suitable for various optical metrology applications.
• This innovation offers a significant reduction in cost compared to existing technologies.