ABSTRACT
This paper describes a full Stokes polarimeter employing a monolithic off-axis polarizing interferometric module and a 2D array sensor. The proposed passive polarimeter provides a dynamic full Stokes vector measurement capability of around 30 Hz. As the proposed polarimeter employs no active devices and is operated by employing an imaging sensor, it has significant potential to become a highly compact polarization sensor for smartphone applications. To show the feasibility of the proposed passive dynamic polarimeter scheme, the full Stokes parameters of a quarter-wave plate are extracted and displayed on a Poincare sphere by varying the polarization state of the measured beam.
ABSTRACT
The depth-gating capacity of a spatially quasi-incoherent imaging interferometer is investigated in relation to the 3D correlation properties of diffraction field laser speckles. The system exploits a phase-stepped imaging Michelson-type interferometer in which spatially quasi-incoherent illumination is generated by passing an unexpanded laser beam through a rotating diffuser. Numerical simulations and optical experiments both verify that the depth-gating capacity of the imaging interferometer scales as λ/2NAp2, where λ is the wavelength of the laser and NAp is the numerical aperture of the illumination. For a set depth gate of 150 µm, the depth-gating capacity of the interferometer is demonstrated by scanning a standard USAF target through the measurement volume. The results obtained show that an imaging tool of this kind is expected to provide useful capabilities for imaging through disturbing media and where a single wavelength is required.
ABSTRACT
This paper describes a robust dynamic spectroscopic ellipsometer that can provide a highly accurate and reliable real-time spectroscopic polarization measurement capability for various in-line nanoscale measurement applications. The robustness of dynamic spectroscopic ellipsometry is enhanced significantly by employing a compensation channel that removes the temperature dependency of the monolithic polarizing interferometric module, and it results in highly accurate dynamic spectral ellipsometric measurements. We present how the monolithic interferometer is affected by external disturbances and show experimentally that the proposed scheme can provide a few hundreds of times long-term stability enhancement compared with a single-channel-based dynamic spectroscopic ellipsometer scheme.
ABSTRACT
A dynamic spectroscopic imaging ellipsometer (DSIE) employing a monolithic polarizing interferometer is described. The proposed DSIE system can provide spatio-spectral ellipsometric phase map data Δ(λ, x) dynamically at a speed of 30â Hz. We demonstrate the ultrafast mapping capability of the spectroscopic ellipsometer by measuring a patterned 8-inch full wafer with a spatial resolution of less than 50 × 50 µm2 in an hour.
Subject(s)
Refractometry , Refractometry/methods , Spectrum Analysis/methodsABSTRACT
A rapid direct spectroscopic ellipsometric parameter extraction algorithm for computational speed enhancement of dynamic spectroscopic ellipsometry is described. The proposed direct spectral phase calculation method can provide a faster spectral phase extraction capability than a Fourier transform-based approach, while maintaining the same level of accuracy as that based on the Fourier transform method. We analyze some additional benefits and limitations of the proposed direct computational method in terms of enlarged Δ(λ) measurement spectral range and precision optimization.
ABSTRACT
This paper describes a new class of ultrafast dynamic spectro-polarimetry based on a specially designed one-piece polarizing interferometer. It provides spectral polarimetric parameters of an anisotropic object in milliseconds with high precision. The proposed ultrafast spectro-polarimetry has no moving parts and it is highly robust to external noises. The one-piece polarizing interferometric scheme enables the world fastest and simplest solution in spectroscopic polarimetry. The distinct simple concept on one-piece polarizing interferometer can extract spectroscopic polarimetric parameters Ψ(k) and Δ(k) precisely with a speed of over 200 Hz over the entire visible wavelength range with a spectral resolution of less than 1 nm. The proposed novel one-piece scheme will have a significant potential of a paradigm shift from lab to fab in polarization metrology.
ABSTRACT
We propose a snapshot spectroscopic ellipsometry and its applications for real-time thin-film thickness measurement. The proposed system employs an interferometric polarization-modulation module that can measure the spectroscopic ellipsometric phase for thin-film deposited on a substrate with a measurement speed of around 20 msec. It requires neither moving parts nor time dependent modulation devices. The accuracy of the proposed interferometric snapshot spectro-ellipsometer is analyzed through comparison with commercial equipment results.
ABSTRACT
A simple dynamic spectro-polarimeter based on a modified Michelson interferometric scheme is described. The proposed system can extract a spectral Stokes vector of a transmissive anisotropic object. Detail theoretical background is derived and experiments are conducted to verify the feasibility of the proposed novel snapshot spectro-polarimeter. The proposed dynamic spectro-polarimeter enables us to extract highly accurate spectral Stokes vector of any transmissive anisotropic object with a frame rate of more than 20Hz.
ABSTRACT
This Letter describes a Stokes vector measurement method based on a snapshot interferometric common-path spectropolarimeter. The proposed scheme, which employs an interferometric polarization-modulation module, can extract the spectral polarimetric parameters Ψ(k) and Δ(k) of a transmissive anisotropic object by which an accurate Stokes vector can be calculated in the spectral domain. It is inherently strongly robust to the object 3D pose variation, since it is designed distinctly so that the measured object can be placed outside of the interferometric module. Experiments are conducted to verify the feasibility of the proposed system. The proposed snapshot scheme enables us to extract the spectral Stokes vector of a transmissive anisotropic object within tens of msec with high accuracy.
