Search

Knowledge of the absolute value of the second order nonlinear optical coefficient of materials plays a key role in assessing the performance. The second harmonic (SH) wave is employed to measure accurately the second order nonlinear coefficient (d36) of the narrow band gap semiconductor, mercury cadmium telluride (MCT).

A more accurate method of obtaining the refractive indices of anisotropic prisms is introduced. Designed for prisms that undergo light polarization orthogonal to a dielectric prism axis, it does not require the orientation of the dielectric axes within a prism. It was developed on prisms made of 4-amino-benzophenone crystals characterized by low defect levels. The fitting of the linear refractive indices of ABP to Sellmeier equations and their verification via external angle of incidence observations is also discussed.

Measurements of linear electro-optic effect in 2-alpha-methylbenzyl-5-nitropyridine show that there is variation in the linear electro-optic effect with respect to the wavelength of incident light. Values of 2.1, 2.8, and 6.0 kilovolts at 488, 514.5 and 632.8 nanometers are exhibited by the methylbenzylamino compound as half voltages. The measurements also enable the variation of birefringence of the compound.

Flash diffusivity method is used to measure the thermal diffusivities of high quality alpha-methylbenzylamino-5 nitropyridine single crystals in different directions. From the various values of thermal diffusivity, specific heat and density data, the complete thermal conductivity tensor at temperatures of 295, 323 and 349 Kelvin are obtained. The Heckman method was used for the evaluation of the thermal diffusivities from temperature time response characteristics by using the least square methods. The value obtained for the thermal conductivity anisotropy is large for these materials.

The linear and nonlinear optical properties of 4-nitro-4'-methylbenzylidene aniline (NMBA) organic material are studied. Large single NMBA crystals are grown by temperature lowering of a seeded supersaturated ethyl acetate solution. The crystals are then subjected to a series of experimental and theoretical analyses. Results reveal that both angle and wavelength noncritical phase matching are possible with the NMBA crystals.

The second order nonlinear coefficient (d[sub 36]) of the narrow band gap semiconductor, mercury cadmium telluride (MCT), is measured. Because MCT is strongly absorbing at a 1.06 μm wavelength, the measurement was performed by comparing the second harmonic intensity reflected from the material surface to the second harmonic intensity measured for a quartz sample in transmission. The analysis depends on the derivation of comparable expressions for the reflected and transmitted intensities. Using this approach a value of d[sub 36]=350±40 pm/V is obtained, a value much larger than those reported for similar zinc-blende type materials. The large magnitude of the MCT d[sub 36] is attributed to an electronic resonance enhancement. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The linear electro-optic effect in 4-nitro-4-methylbenzylidene aniline single crystals was analyzed. The half-wave voltages were measured at 2.8, 1.3 and 1.1kV at 632.8, 514.5 and 488.0 nm. The results showed that the crystal features asignificant electro-optic effect. In addition, the birefringence was observed to be larger than that found in inorganic materials.

The variation of the linear electro-optic effect in (-)-2-(α-methylbenzylamino)-5-nitropyridine with the wavelength of the incident light at room temperature has been measured. The reduced half-wave voltages have been found to have the values 2.1, 2.8, and 6.0 kV at 488, 514.5, and 632.8 nm respectively and the corresponding values of the linear electro-optic coefficient have been evaluated. The interpretation of the results in terms of the structures of the molecule and the crystal is discussed. The thermal variation of the birefringence has also been investigated and the coefficient for the temperature variation of the refractive index difference is found to have the value (dΔn/dT)=9.3×10-5 K-1. [ABSTRACT FROM AUTHOR]

Presets a study that measured thermal diffusivities of high quality (-)2-(α-methylbenzylamino)-5-nitropyridine single crystals in different directions by the flash diffusivity method. Information on specific heat and density; Determination of the thermal conductivity tensor; Conclusion.