Single-sequence stable spectroscopic reflectometry using simultaneous measurement of incident light and reflected...

Area of Science:

• Optics and Photonics
• Materials Science
• Spectroscopy

Background:

• Spectroscopic reflectometry (SR) is crucial for thin film characterization.
• Intensity variations in incident light can compromise measurement stability and accuracy.
• Current SR methods may involve complex procedures for stable measurements.

Purpose of the Study:

• To introduce a novel SR scheme that enhances stability against incident light intensity variations.
• To simplify the measurement procedure in SR.
• To enable simultaneous measurement of incident and reflected light.

Main Methods:

• Modulating incident light intensity into a high-frequency signal using a multi-order retarder in the spectral domain.
• Simultaneously measuring both incident and reflected light.
• Employing Fourier transform to separate the superimposed signals detected by the spectrometer.

Main Results:

• The proposed SR method demonstrates improved stability under varying incident light intensities.
• The technique successfully separates incident and reflected light signals.
• Accurate measurements of SiO2 thin films on Si substrates were achieved, validating the method.

Conclusions:

• The new SR scheme offers enhanced stability and simplified procedures for thin film analysis.
• Simultaneous detection and Fourier transform processing effectively overcome challenges posed by light intensity fluctuations.
• This method provides a robust approach for precise thin film characterization in materials science and optics.