M. Drozdowski

Optical properties of KGd(WO4)2 single crystals studied by Brillouin spectroscopy

The analysis some of the acoustic phonons propagating in pure and Ho3+-doped KGd(WO4)2 single crystals in the GHz frequency range by Brillouin scattering method has been presented. For investigated crystals the velocities of the longitudinal and transverse acoustic phonons [100], [010], [001], [101], [101] and [110] have been determined. Moreover, the value of elastic constants C22, C44 and C66 of pure and Ho3+-doped KGd(WO4)2 single crystals have been estimated. It was revealed that the presence of the Ho3+-ions in KGd(WO4)2 crystals, for the used doping concentration 1 at% and 8 at%, does not influence their elastic properties. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Phase transition study of 1,4-butanediol dimethacrylate by the optical Kerr effect and Brillouin light scattering☆

Abstract We report the results of a temperature study of the optical Kerr effect in 1,4-butanediol dimethacrylate (BDM) revealing a phase transition in the temperature range from 295 to 302 K. Using the Brillouin light scattering method we have also studied the temperature behaviour of the sound velocity and the elasto-optic of BDM. The above temperature dependences display a characteristic discontinuity at about 298 K.

Temperature study of lattice constants and Raman scattering of SrLaGaO4 single crystal

The lattice parameters of SrLaGaO4 (SLG) single crystal were measured in the temperature range from 300 to 700 K using X-ray spectroscopy. The measurements revealed that (i) the thermal coefficient along a and c axes is different and (ii) thermal expansion coefficient in a direction depends on temperature, showing the transition temperature at about 460 K. To verify this result we have also studied the Raman intensity IR and full width at half maximum (FWHM) of the Raman band at 218 cm−1 ascribed to the librational lattice mode. The above temperature dependences display a characteristic discontinuity at about 460 K which coincides with the previous data obtained from X-ray measurements. The obtained results are discussed in terms of the nature of defects which might arise in the ABCO4 lattice during the crystal growth process.

Molecular dynamics of poly(ethylene glycol)s studied by optical Kerr effect and Brillouin spectroscopy

The optical Kerr effect and Brillouin scattering study of a series of poly(ethylene glycol)s (PEGs) in the function of temperature and molecular weight (MW) have been performed. The obtained results enabled us to determine some macroscopic and microscopic parameters (such as molecular Kerr constant, hypersonic velocity, adiabatic compressibility), of the compounds investigated. The values of these parameters were found to depend strongly on both temperature and PEGs MW. Analysis of the results indicates on the presence of molecular interactions leading to formation of molecular aggregates. The increase in the MW leads to folding of PEG chains and to formation of statistical coils.

Characterization of the elastic and elasto-optic properties of SrLaAlO4 and SrLaGaO4 crystals using the Brillouin scattering method

Abstract The review of the elastic and elasto-optic properties of SrLaAlO 4 (SLA) and SrLaGaO 4 (SLG) crystals grown by Czochralski method is presented. After a brief description of the Brillouin scattering method, used in the characterization of the elastic and elasto-optic properties, the experimental results obtained for SLA and SLG crystals by this method are surveyed. The obtained results are also discussed in terms of the oxygen point defects which might be created in the crystal during the growth process.

Raman scattering study of the ferroelectric phase transition in GPI and DGPI single crystals

Abstract The Raman spectra of GPI and DGPI crystals were investigated in the 400–3200 cm−1 internal vibrations range and in the temperature range 175–250 K and 295–355 K, respectively. Para-ferroelectric phase transition at 224 K for GPI and 322 K for DGPI was examined. The results obtained from Raman investigations confirm the order-disorder nature of a ferroelectric phase transition of second order type. One type of glycinium cations is observed in the paraelectric phase but two types in ferroelectric phase. The dynamical disorder of protons is coupled to the motions of glycinium cations.

Temperature study of the elastic properties of glycinium phosphite and deuterated glycinium phosphite crystals by brillouin scattering

Abstract Brillouin spectroscopy was used to study the elastic properties of glycinium phosphite (GPI) and deuterated glycinium phosphite (DGPI) crystals. The temperature measurements of the hypersonic velocity for acoustic modes propagating in various directions have been performed in the temperature range 170 K-300 K and 295 K-355 K for GPI and DGPI, respectively. Brillouin study has confirmed the existence of the order-disorder type ferroelectric phase transition (P21/a - P21) at 224 K for GPI and 322 K for DGPI. The obtained results are also discussed in terms of the reordering of the hydrogen bonds in the ferroelectric phase.

Anisotropy of the Elastooptic Properties of SLA and SLG Crystals Studied by Brillouin Scattering

The influence of annealing of SrLaAlO 4 (SLA) and SrLaGaO 4 (SLG) crystals on their elastooptic properties has been reported. The results obtained are discussed in terms of the nature of the oxygen point defects which might be created in the crystals during the growth process.

Optical Properties of Bismuth Triborate (BIBO) Single Crystals

We present a study of the nonlinear optical and elasto-optic properties of BiB 3 O 6 (BIBO) crystal. The estimated values of the nonlinear optical coefficients d ij are compared with the previously published values. Efficiency of the phase matched SHG and optical damage threshold for Q-switched Nd-YAG laser radiation are reported as well. The elastooptic constants p ij corresponding to the acoustic phonons propagating in q = [100], q = [010], q = [001], q = [110], q = [101] directions were estimated using Brillouin scattering method.

Study of the elastic and elastooptic properties of Zn1−xBexSe solid solutions by Brillouin spectroscopy

We report experimental results concerning the elastic and elastooptic properties of Zn1−xBexSe solid solutions grown by the high pressure Bridgman technique. The elastic and elastooptic constants of Zn1−xBexSe crystals with different Be content have been determined at room temperature by the Brillouin scattering method.