Angle-resolving spectral ellipsometry using structured light for direct measurement of ellipsometric parameters

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Traditional ellipsometry often requires complex optical setups and moving components.
• Achieving high resolution in both spectral and angular domains simultaneously presents a significant challenge.

Purpose of the Study:

• To introduce a compact and efficient angle-resolving spectral ellipsometry system.
• To demonstrate a novel method for precise thin-film characterization using structured light.

Main Methods:

• Utilizing a digital micro-mirror device (DMD) to generate structured light patterns.
• Illuminating the back focal plane of a high numerical aperture (NA) objective lens.
• Employing a spectrometer for spectral acquisition and a fiber for micro-scale spot size reduction.

Main Results:

• Direct measurement of ellipsometric parameters with high resolution in wavelength (0.7 nm) and incidence angle (<1°).
• Demonstrated precise thin-film thickness measurements from 410 to 700 nm.
• Validated accuracy and precision against a commercial ellipsometer.

Conclusions:

• The proposed DMD-based spectral ellipsometry offers a simplified, faster, and highly accurate method for thin-film analysis.
• This technique eliminates the need for rotating optical components, enhancing system robustness.
• The system is capable of precise characterization of thin films in both spectral and angular domains.