Optical determination of the thickness of 2D flakes of the superconductor

Key Points

• This research aims to measure the thickness of 2D superconducting flakes using optical contrast methods.
• Conducted optical contrast measurements under controlled atmospheric conditions.
• Utilized optical interference models to analyze samples of FeSe ranging from 5 to 300 nm.
• Calculated refractive index as a function of wavelength based on the optical contrast.
• Developed optical contrast maps to assess sample thickness and degradation.
• Demonstrated that calculated optical contrast maps are effective for detecting thinner flakes.
• Highlighted sensitivity of optical contrast to small variations in complex refractive index.
• Established a method to monitor sample degradation through optical contrast measurements.