Total external reflection

About: Total external reflection is a research topic. Over the lifetime, 829 publications have been published within this topic receiving 22213 citations.

Reflection and refraction of waves in oscillatory media

Abstract: This paper uses the two-dimensional Brusselator model to study reflection and refraction of chemical waves. It presents some boundary conditions of chemical waves, with which occurence of observed phenomena at interface as refraction and reflection of chemical waves can be interpreted. Moreover, the angle of reflection may be calculated by using the boundary conditions. It finds that reflection and refraction of chemical waves can occur simultaneously even if plane wave goes from a medium with higher speed to a medium with lower speed, provided the incident angle is larger than the critical angle.

Device for controlling radiation and uses thereof

Abstract: not available for EP0555376Abstract of corresponding document: WO9208235A device for controlling beams of particles, X-rays and gamma rays including a plurality of channels with total external reflection inner surfaces, input butt-ends facing a radiation source and output butt-ends aimed at a radiation receiver is taught. Channel-forming elements are in the form of surfaces, tubes, and structures with multiple channels and are rigidly positioned one relative to another with a spacing between suports such that the sagging of the channel-forming elements does not interfere with beam propagation. The device can be used to capture radiation from sources which produce parallel or divergent radiation. The resulting beam or beams can be of a variety of shapes or angular orientations including quasi-parallel, convergent, and split beams. Energy filtering is accomplished by selective absortion of radiation by the channel-forming elements and by selective reflection, by geometrics which cause some energies to be discriminated against because of the angle of total external reflection associated with that energy. Also provided are embodiments which use these devices for improved medical imaging, medical therapy, X-ray lithography, and analytic instruments.

A method for measuring the continuous dispersion spectrum of nonlinear refraction coefficients of materials

Abstract: In this paper, a method for measuring the continuous dispersion spectrum of nonlinear refraction coefficients of materials based on complex refractive index dispersion (CRID) measurement is proposed. This method involves measuring internal reflection spectra with a lab-made apparatus. From the determined CRIDs of a material with and without exciting light, the changes in refractive index over a wide spectral range can be obtained, from which the nonlinear refraction coefficients can be deduced. In addition, the RI changes at wavelengths far from the nonlinear range can be used to monitor the thermal effects. In this study, a methyl-red-doped poly(methyl methacrylate) (MR-PMMA) sample was investigated. A large nonlinear refraction coefficient on the order of 10 −1 cm 2 /W was observed. The results also show that the absolute value of nonlinear refraction coefficient of the MR-PMMA sample decreases with the increase of excitation intensity. Consequently, this study provides a powerful approach that has the potential to be applied in the study of the nonlinear properties of materials.

Formation of a metastable superlattice by x‐ray interaction with standing surface acoustic waves

Abstract: X‐ray diffraction on the surface of the YZ cut of a LiNbO3 ferroelectric crystal modulated by standing surface acoustic waves (SAW) was investigated under the total external reflection conditions. It is shown that a metastable superlattice is formed in the near‐surface region in the process of the interaction between the incident x‐ray radiation and the ferroelectric crystal surface modulated by standing SAW. The metastable superlattice may be stored for a long time period and may be read out by x‐ray and laser radiation.

Method for the measurement of the refractive index of a thin layer

Abstract: A method for the measurement of the refractive index of a thin layer, which is formed on another layer having a known refractive index, has the following steps: first, the thin layer is irradiated individually at a predetermined angle of incidence with S-polarised and P-polarised monochromatic light; then energy reflection ratios Rs and Rp are determined for the S-polarised and P-polarised monochromatic light; hereupon the light intensity of the reflected light from the thin layer is then determined and, finally, the refractive index of the thin layer is measured by means of a prescribed calculation on the basis of phase value changes of the light during its propagation from an upper surface of the thin layer to its lower layer, the phase changes corresponding to the refractive index of the medium and to the energy reflection ratios Rs and Rp being determined.