Optical balanced detection in heterodyne interferometric ellipsometry.

Area of Science:

• Optics and Photonics
• Interferometry
• Polarimetry

Background:

• Ellipsometry is a powerful technique for characterizing thin films and surfaces.
• Traditional ellipsometry setups can be sensitive to environmental noise and vibrations.
• Real-time measurement of ellipsometric angles is crucial for dynamic processes.

Purpose of the Study:

• To develop a novel common path heterodyne interferometer for real-time ellipsometric angle measurement.
• To implement optical balanced detection for effective noise reduction.
• To achieve accurate determination of ellipsometric angles using maximum likelihood estimation.

Main Methods:

• A common path heterodyne interferometer design was employed.
• Optical balanced detection was integrated for noise suppression.
• Quadrature interference amplitudes and phase information were analyzed using maximum likelihood estimation.

Main Results:

• The system successfully measured ellipsometric angles in real time.
• Significant reduction in interference noise was achieved.
• Accurate determination of ellipsometric angles was demonstrated.

Conclusions:

• The proposed common path heterodyne interferometer with optical balanced detection offers a robust solution for accurate, real-time ellipsometry.
• This method effectively mitigates noise, improving measurement precision.
• The technique is suitable for applications requiring precise optical characterization.