Broadband femtosecond spectroscopic ellipsometry

Area of Science:

• Materials Science
• Spectroscopy
• Optics

Background:

• Time-resolved spectroscopic ellipsometry is crucial for understanding ultrafast material dynamics.
• Existing setups face challenges in temporal resolution and spectral range.

Purpose of the Study:

• To present a novel setup for time-resolved spectroscopic ellipsometry.
• To achieve high temporal resolution and broad spectral coverage for pump-probe experiments.

Main Methods:

• Utilized femtosecond laser pulses in a pump-probe configuration.
• Employed supercontinuum white light as the probe pulse, delayed relative to the pump.
• Implemented a polarizer-sample-compensator-analyzer setup for ellipsometric measurements.
• Scanned compensator azimuthal angle to obtain transient ellipsometric parameters from reflectance-difference spectra.

Main Results:

• Achieved a temporal resolution of approximately 100 fs.
• Covered a spectral range from near-infrared to near-ultraviolet (1.3 eV–3.6 eV).
• Demonstrated measurements over a delay range exceeding 5 ns.
• Analyzed and addressed issues related to probe pulse fluctuations and polarization optics imperfections.

Conclusions:

• The developed setup enables high-resolution, time-resolved spectroscopic ellipsometry.
• The system is suitable for investigating ultrafast phenomena in materials across a wide spectral range.
• Strategies for overcoming technical challenges ensure reliable data acquisition.