Originally posted by matrix_204
Could anyone please explain me the concept of light waves and the information about polarization.
Light waves, depending on the context, usually refer to electromagnetic waves in the region of the spectrum around the visible frequencies/wavelengths. This includes the colors you see (visible region), and usually also considers down to the far infrared and up to the far ultraviolet. Millimeter waves, the next region down from infrared, are usually considered as radiowaves as opposed to light waves. X-rays, the next region up from ultraviolet, are usually considered as high energy radiation, as opposed to light waves. They are all electromagnetic, though, and the naming convention is secondary to the physics.
As electromagnetic waves, some generalities can be made. There are two fields involved, the electric and the magnetic. (Really these are just two ways in which the same fundamental field manifests. This is probably beyond the scope of what you are trying to understand.) The electric and magnetic field vectors are perpendicular to each other in the wave. They are both also perpendicular to the direction of the wave, and so the wave is called "transverse." The polarization is defined by the direction of the electric field vector. (You will probably only be dealing with linear polarization. For this, the polarization does not change direction.)
For the wave traveling in the z direction, the electric and magnetic fields oscillate in the x-y plane. Let's say that the x-direction is horizontal, and the y-direction is vertical. If the electric field oscialates in the x-direction, then the wave is horizontally polarized. If the electric field oscillates in the y-direction, then the wave is vertically polarized. If the electric field oscillates in some direction that makes some angle, θ, with respect to the x(or y)-axis, then the wave has a polarization angle of θ with respect to the x(or y)-axis.
I guess I don't really have any more to say about this.
Originally posted by matrix_204
Also the inferometers ...
I'm assuming you meant to write "interferometers." An interferometer is, generally, an piece of equipment designed for the purpose of causing interference. General waves can be thought of as composed of more fundamental constituents, called plane waves. A plane wave is a sinusoidal variation in space and time. In general, waves are not sinusoidal. We break them up into sinusoidal consituents because sinusoids are easier to manipulate in calculations. You will probably only be considering plane waves, so this decomposition is somewhat trivial, but it gives insight into how interference works.
In a way, waves exist everywhere in the region of interest. The wave is the value of the thing that is waving at every point in space and time. So, you can think of two light beams as two distinct light waves, or you can think of this situation as one wave that is the sum of the two individual beams. Where one beam is zero, the total wave is just trivially the other beam. But, in the region of space where both beams meet, the total wave is a nontrivial sum of the two. Mathematically it is a sum. Physically it is interference. It is straightforward. If the E-field of one of the beams is in the same direction at a point as the E-field from the other beam, there is
constructive interference. The total E-field is the sum of the two individual E-fields. If the individual E-fields are the same size but pointing in opposite directions at some point in space, there is
destructive interference, and the total E-field, being the sum of the individual E-fields, is naturally zero. This is called the principle of superposition.
Since the waves are functions of space and time, in general these points of constructive and destructive interference will move around. If the light is coherent, then it is possible to establish stable, nonmoving patterns. Usually, interferometers have a viewing screen, which is just choosing a region of space to observe the interference. The interference happens everywhere where the two beams exist in the same space, but you usually are only interested in what is happening on the screen.
Originally posted by matrix_204
... or some stuff on nodal lines, ...
I don't know what is meant by nodal line, but, I would assume, if this is in the context of an interferometer, that this refers to the dark lines that appear on the screen of the interferometer. They appear dark because on these lines there is destructive interference of two (at least) beams of light. I should mention that the light can be from the same source. A beam splitter can be used to separate the light into two beams so that the light from this common source can be made to interfer with itself.