Phase shifting and phase retrieval with a fully automated laser diode system.

Area of Science:

• Optical metrology
• Interferometry
• Laser physics

Background:

• Phase-shifting interferometry (PSI) is crucial for precise optical measurements.
• Traditional PSI setups can be complex and require extensive calibration.
• Automated, cost-effective PSI methods are needed for broader applications.

Purpose of the Study:

• To develop a low-cost, fully automated phase-shifting interferometry system.
• To demonstrate phase retrieval without prior calibration.
• To simplify the optical setup for PSI.

Main Methods:

• Utilized an unbalanced Twyman-Green interferometer (TGI) setup.
• Employed a tunable laser diode (LD) with continuously varied input voltage.
• Implemented a data acquisition (NI-DAQ) device for laser control.
• Automated data acquisition and analysis using LabVIEW and MATLAB.
• Applied the Carré algorithm for phase map retrieval.

Main Results:

• Successfully obtained phase maps using the automated TGI setup.
• Verified PSI requirements through measurements of visibility and phase shift.
• Demonstrated accurate phase retrieval without calibration.
• Showcased the system's effectiveness with experimental results and statistical analysis.

Conclusions:

• The developed low-cost, automated PSI system is effective for phase retrieval.
• Minimal optical components and no calibration are required for successful operation.
• This approach offers a simplified and accessible method for optical metrology.