Phase measuring Ronchi test.

Area of Science:

• Optical metrology
• Wavefront sensing
• Aspheric surface analysis

Background:

• The Ronchi test is a common optical testing method.
• Measuring large wavefront aberrations or aspheric wavefronts presents challenges with conventional techniques.

Purpose of the Study:

• To introduce and validate synchronous phase detection for the Ronchi test.
• To enable precise measurement of large wavefront aberrations and aspheric surfaces.

Main Methods:

• Implementing synchronous phase detection by laterally shifting the Ronchi grating.
• Introducing a periodic phase shift in the Ronchigram for analysis.
• Developing a theoretical interpretation of the modified Ronchigram.

Main Results:

• Demonstrated a simple yet powerful tool for aspheric surface evaluation.
• Successfully measured significant wavefront aberrations using the enhanced Ronchi test.
• Experimental results validate the theoretical interpretation and procedure.

Conclusions:

• Synchronous phase detection is an effective enhancement to the Ronchi test.
• This method simplifies the evaluation of aspheric surfaces.
• The technique is suitable for measuring large wavefront aberrations.