Refracted ray

Fig. 18.4, designates the optical path for the upper prism in Abbe Refractometer. When a ray of light passes from the liquid medium and enters the upper prism, it gets refracted by an angle 0 between the lower face of the prism and the normal, an angle P between the emerging refracted ray at the upper face and the normal, and finally an angle a between the reflected ray at the upper face and the normal. Thus, we have ... 

A physical picture of refraction at an interface shows TIR to be part of a continuum, rather than a sudden new phenomenon appearing at 8 = 8C. For small 8, the light waves in the liquid are sinusoidal, with a certain characteristic period noted as one moves normally away from the surface. As 8 approaches 0,., that period becomes longer as the refracted rays propagate increasingly parallel to the surface. At exactly 8 = 0C, that period is infinite, as the wave fronts of the refracted light are normal to the surface. This situation... 

When an acoustic wave is incident on a planar boundary at an angle other than normal, each refracted ray obeys Snell s law... 

In some cases, especially with almost colourless liquids, the zones of the field of vision exhibit somewhat different colours, which prevents accurate readings being obtained. This inconvenience is avoided by introducing a suitable plate of potassium bichromate into the eye-piece or by interposing between the lamp and the saccharimeter a glass cell with parallel faces (Landolt s so-called ray-filter) containing an aqueous solution of this salt1 by this means the more refractive rays are absorbed and the field assumes a uniform yellow tint. 

Extraordinary ray A refracted ray in biaxial crystals which does not obey the ordinary laws of refraction because its velocity varies with direction through the crystal. 

Ordinary ray A refracted ray that obeys the laws of refraction. It moves with equal velocity in all directions through a crystal. 

The specimen is optically anisotropic and is being viewed in monochromatic light and the combination of specimen thickness and birefringence represents a path difference of integral wavelength for the two refracted rays ... 

It is noted that only for values of 6 greater than 6 will there be no refracted ray such that light is totally internally reflected at the interface and propagates within the medium of... 

The reflection and refraction of electromagnetic radiation at an interface can be discussed with relation to Fig. 2. The incident, reflected, and refracted rays are shown in this figure as I, R, and T and reflection and transmission coefficients can be derived straightforwardly from standard electromagnetic theory. In order to focus our ideas and to define the convention used in this section, we may write down the expression for the electric field, E, of the radiation, assuming that the light is propagating in the z direction (with unit vector ) and the electric field is oriented in the x direction (with unit vector... 

Figure 7.1 Geometry of scattering (and reflection) from surface, ko, k, and k are the wave vectors for the incident, reflected, and refracted rays.

When radiation is incident on an interface between two materials, part of the energy is reflected at the interface and the rest is transmitted through it. Irrespective of whether the radiation involved is a beam of light, x-rays, or neutrons, the geometry and the relative intensities of the reflected and refracted rays can be described by the principles of optics,4 once the refractive indices of the two media are known. The concept of refractive indices of neutrons was briefly introduced in Section... 

At a sharp, planar boundary between two homogeneous media of refractive indices no and n both the reflected and refracted rays are in the plane of incidence (the plane containing the incident ray and the normal to the boundary). The angle 0 of reflection is related to the angle 0o of incidence (see Figure 7.3) by the law of reflection... 

VI. To find the conditions which must subsist in order that light may travel from a given point in one medium to a given point in another medium in the shortest possible time. Let SP (Fig. 77) be a ray of light incident at P on the surface of separation of the media M and M let PR be the refracted ray in the same plane as the incident... 

Birefringence - A property of certain crystals in which two refracted rays result from a single incident light ray. One, the ordinary ray, follows the normal laws of refraction, while the other, the extraordinary ray, exhibits a variable refractive index which depends on the direction in the crystal. 

For external incidence, the Mueller matrices of the reflected and refracted rays (denoted by subscripts r and t) can be obtained from... 

Where n is the refractive index, e the permittivity and p the permeability of the dielectric media. The incident, reflected and refracted rays are coplanar (located in the x-z plane, the plane of incidence, in Fig. 14.36). Transverse electric (TE), perpendicular (-L) or s-polarised light has its electric vector perpendicular to the plane of incidence (x-z plane) in Fig. 14.36, while transverse magnetic (TM), parallel ( ) or p-polarised light has its magnetic vector perpendicular to the plane of incidence. 

The Fresnel equations describe the reflection and transmission coefficients at the interface of two optical media. The polarisation of the incident Hght affects the magnitude of these coefficients. It is possible to derive expressions for the intensities of the reflected and refracted rays. These differ for the TE and TM polarisations as follows ... 

---