Optical characteristics of triclinic rubidium hydrogen selenate

Abstract

The refractive indices of rubidium hydrogen selenate are measured for several wavelengths at room temperature, and the transmission spectrum is measured from the UV (240 nm) to the near IR (2000 nm). The orientation of the optical indicatrix with respect to the crystal axes is also determined at several wavelengths in the visible range. Using a new method based on the deflection o f l ight b y t he f erroelastic d omain structure, we also determine refined values for birefringence at several w avelengths. Finally, the dispersion of the three birefringences in the range 450-900 nm is deduced from polarimetric measurements. This set of results yields complete knowledge of the linear optical characteristics required for interpretation of the electro-optical and nonlinear optical properties of this compound.

Correlation between dielectric and electro-optic properties related to domain dynamics inRbHSeO4crystals

“…All dielectric and EO responses observed in RHSe, i.e., with ac and dc fields and with frequency, can be attributed to both the specific domain structure and domain dynamics of this material. This domain structure appears under a polarizing microscope as layered strips, with domain thickness varying from 1 to 100 m. 12 The so-called ''initial'' dielectric permittivity measured in the coercive state under small ac-field amplitudes is small and slightly frequency dependent ͑400 to 250͒. It can be mainly attributed to the ionic contribution, superimposed with a slight domain contribution probably due to domain-wall oscillations.…”

“…Additionally, it was also found 12 that the corresponding birefringence ⌬n 1 ͑0.0560 at 633 nm͒ is much larger than ⌬n 2 ͑0.0139 at 633 nm͒. Since the indirect Pockels coefficients r 42 and r 52 related to domain dynamics should be proportional to the corresponding products ⌬n i ϫsin 2 i , it can be expected that the largest Pockels coefficient of RHSe in the polydomain state should be r 42 .…”

“…These two coefficients describe the field-induced tilt motions of the optical indicatrix, around the x 1 axis and x 2 axis, respectively, which are defined as the optical neutral lines in the (a,b) plane of domain walls. 12 We have recently measured 12 the natural tilt angles of the optical indicatrix with respect to domain walls ͑Fig. 6͒ in polydomain RHSe crystals: at 633 nm the tilt angle 1 around the x 1 axis ͑2.2°͒ is larger than the tilt angle 2 around the x 2 axis ͑0.6°͒.…”

Combined effects due to phase, intensity, and contrast in electrooptic modulation: application to ferroelectric materials

“…Similar phenomena can be observed with ferroelectric crystals exhibiting a layered domain structure. In such crystals, where the domain walls are all of the same kind and parallel to each other, the deflection phenomenon gives-as a rule-six beams [7], [8], schematically shown in Fig. 3(b).…”

“…We shall consider both experiments, performed on RHSe. The physical and optical characteristics of this crystal are published elsewhere [8].…”