Ellipsometric

Ellipsometric refers to a technique called ellipsometry, which is an optical method used to study the optical properties of a material. It is a sensitive technique that measures the change in polarization of light upon reflection from or transmission through a sample. The polarization state of light is a fundamental property that describes the orientation of the electric field oscillations. Ellipsometry precisely measures how this polarization state is altered by an optical interface or a thin film.

The technique works by illuminating a sample with polarized light at a specific angle of incidence. As the light interacts with the sample, its polarization state changes due to reflection and/or transmission. Ellipsometry measures this change by analyzing the reflected or transmitted light. The measured quantities, typically denoted as Psi (Ψ) and Delta (Δ), are then used to determine the dielectric function or refractive index and extinction coefficient of the material. These optical constants are characteristic properties of a material and can provide information about its composition, structure, and electronic properties.

Ellipsometry is a non-destructive technique and can be applied to a wide range of materials, including semiconductors, dielectrics, metals, polymers, and biological samples. It is particularly useful for characterizing thin films, such as those used in microelectronics, optical coatings, and sensors, as it can determine film thickness and optical properties with high accuracy. Different types of ellipsometers exist, including rotating analyzer ellipsometers, rotating retarder ellipsometers, and phase-modulated ellipsometers, each offering various advantages in terms of speed and sensitivity.