Angle resolved Mueller polarimetry with a high numerical aperture and characterization of transparent biaxial samples

Abstract

We present a polarimetric instrument suitable for the simultaneous measurement of angle resolved normalized Mueller matrices for polar angles ranging from 0 degrees to 60 degrees and all azimuths. The polarimetric modulation and analysis are performed by means of an optimized polarization state generator and analyzer based on nematic liquid crystals. A high numerical aperture (0.95) microscope objective is used in double pass to illuminate the sample, with its rear focal plane imaged on a low noise CCD. This polarimeter can be used either in reflection, with the sample set in the objective front focal plane, or in transmission, for thin transparent samples. This latter configuration, which involves an additional spherical mirror with its center of curvature at the objective front focus, is described in detail. This instrument was used to accurately determine the directions of the optic axes and the angular dependence of the retardation of a biaxial polyethylene terephthalate (PET) plastic substrate in spite of the strong depolarization essentially due to the source 10 nm spectral width or the limitation in angular resolution due to the pixels distribution of the CCD combined with the sample large retardation.

Modeling the optical properties of self-organized arrays of liquid crystal defects

“…We used a micro-ellipsometry setup allowing local measurements of the Mueller matrix elements at a wavelength of 633 nm on an area with a film of known thickness [15]. The core of the instrument is schematized in Fig.3.…”

“…BFP : Back Focal Plane of the objective. PSG, PSA : polarization state generator and analyzer [15,16].…”

Depolarization effect of bandwidth in Mueller matrix imaging polarimetry

“…More significantly, the depolarization effect will have an influence on the measurement accuracy, and it must be considered in the optical model. Several researchers have investigated the depolarization effect of polarimetric components such as polarizers and compensators in previous work [3,4] . In this work, we focus on the depolarization effect of bandwidth in MMIP and demonstrate that this effect can induce significant measurement errors.…”

Snapshot Mueller matrix polarimetry by wavelength polarization coding and application to the study of switching dynamics in a ferroelectric liquid crystal cell.

“…It is of current use in various scientific fields from material science to medical diagnosis. To provide a more complete characterization, MMs are coupled with other variables such as wavelength in spectropolarimeters [1], space coordinates in imaging polarimeters [2] and wave vector in angle-resolved polarimeters [3]. However, it appears that, among the possible variables, the time one has not yet been a subject of focus for investigations.…”

“…EPJ Web of Conferences (e,e+¨e 2 ,5e+¨e 3 ,5e+¨e 4 ) and the phases associated to the thickness errors ¨e 2 , ¨e 3 , ¨e 4 by I 2 , I 3 , I 4 given that I p = (2ʌ¨n¨e p )/Ȝ 0 (p = 2,3,4). The new relationships between the Fourier peaks and the Mueller coefficients are available in reference[9].…”