Optical media and target characterization by Mueller matrix decomposition

Abstract

Laser imaging set-ups permit characterization of the vectorial nature of the optical wave which is transmitted by a medium or reflected by a target, from polarimetric formalisms such as Jones or Stokes - Mueller calculi. When the Mueller matrix of targets (or media) is experimentally determined, information about the polarizing and depolarizing properties can be obtained from a Mueller - Jones matrix, which operation requires knowledge of the experimental uncertainties in the elements of . We will discuss the possibility of a polar decomposition of the extracted Mueller - Jones matrix. We then obtain the product of a Hermitian matrix and a unitary matrix, which can be associated with it, for a polarization transformer, with an elliptical partial polarizer and a pure elliptical retarder respectively. Classification of a target is deduced from its polarimetric characteristics (depolarization, polarizing and retardation properties). Experimental Mueller matrices of polarization transformers (media or targets) are provided and analysed by this method in order to characterize the physical behaviour of these optical systems with respect to polarization phenomena.

Polarimetry of light scattered by surface roughness and textured films and periodic structures in nanotechnologies: a new challenge in instrumentation and modeling

“…Depolarization effects can be observed when refining models. Reported [1,4,5] data of Mueller matrices for surfaces with different roughness corroborate these observations.…”

“…As shown in figure 2, together with the analytical equation (8), in the [S, p D ] space, the Al data (filled triangles), remain in a very high reflectivity limit Fig. 1 Showing Entropy/depolarization space The Collected data correspond to various references sources [3,4], including data from Ramsey [5], for aluminum surfaces wth roughness ranging from 1.2 microns down to 100nm.The dash line is equation (8). The SiNW film are considered as a distribution of micro crystals components, (needle-like and various shaped nanocrystals), turning to nano-sized light-scatterers, as revealed by Scanning Electron Microscopy, SEM, observation see figure 3,.…”

“…To another extent, Mueller polarimetry reveals much more accuratel surface roughness potential. The pioneer works has been accomplished by Leroy-Brehonnet [4], In some cases the former effective medium approximation (EMA) theory remains not sufficient when processing accurate SE data. Depolarization effects can be observed when refining models.…”

“…The corresponding coherency <[T]> is also diagonal: In the [entropy S, D] space, it will turn in term of a zero 4x4 matrix with the only non zero elements equal to 1,m,m. Each probability p i can be determinate and yields the analytical value of the entropy S. In a complementary approach [4], the depolarization factor (depol), can be express in term of m. In the isotropic case, theҏ >Sѽ ҏ , D@ space is transformed into an entropy versus, depolarization space, i.e. [S, p D =1-depol] The m value from S.R.…”

“…Cloude [7,8], has been replaced by p D =1-depol, a parameter which can be deduced from the depolarization measurements. It yields [4] …”