Spectroscopic ellipsometry of anisotropic materials: application to the optical constants of HgI_2

Abstract

A variable angle-of-incidence spectroscopic fixed-polarizer, rotating-polarizer, fixed-analyzer ellipsometer (PRPSE) across a spectral range from 300 to 800 nm is used to determine the optical properties of anisotropic uniaxial tetragonal red mercuric iodide (HgI(2)). For the first time, to our knowledge, the bulk crystal HgI(2) surface measured by ellipsometry was not subjected to potassium iodide cutting or etching. Measurements were made at an air-HgI(2) interface with the optic axis parallel to the sample surface. To determine the optical constants, we varied both the angle of incidence and the azimuth of the optic axis with the plane of incidence. The detailed formulas needed for reliable procedures for analyzing the data are presented. The ordinary and extraordinary complex indices of refraction, (n(o)--ik(o)) and (n(e)--ik(e)), respectively, are determined. Good agreement between PRPSE and the prism technique for the refractive index is observed. The surface aging effects of the ellipsometric parameters of HgI(2), during 30 h of exposure to air, were detected by PRPSE.

Ellipsometry on Anisotropic Materials: Bragg Conditions and Phonons in Dielectric Helical Thin Films

“…Different techniques exist for acquisition of GE parameters from anisotropic samples, and details are given in Refs. [7,9,11,12,22] and references therein.…”

“…Generalized Ellipsometry (GE), originally introduced by Azzam and Bashara [9], emerged recently as a new global approach for characterization of the optical and structural properties of general anisotropic layered materials, and can be applied for wavelengths from the far infrared to the deep ultra violet [6]. This technique, which provides normalized Jones reflection or transmission matrix elements [10], is very feasible for studying structural and dielectric properties of birefringent media [7,[11][12][13][14][15][16][17][18][19][20][21][22][23][24].…”

Characterizing dielectric tensors from angle-of-incidence Mueller matrix images

“…Another way to characterize the dielectric tensor is by taking measurements at a range of wavelengths and using a fitting routine. 1,6,16 Our method measures multi-angle Mueller matrix images with a polarimeter. The measurement technique is discussed in Section 2.…”

“…2 By measuring a Mueller matrix angle-of-incidence image, the dielectric tensor and thickness can be determined for anisotropic materials such as birefringent structures and polarizing films. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] The need to accurately determine optical properties of anisotropic materials has become a priority with the rapid advancement of liquid crystal displays and the development of new materials along with new fabrication techniques.…”

Determination of Complex Optical Constants of Uniaxial HgI2 by Spectroscopic Conventional and Generalized Ellipsometry

“…For a more detailed description of instrumentation, systematic errors, and performance of this ellipsometer we refer to Refs. [3,4].…”