![]() ![]() ![]() It is very important to realise that the time averaged light intensity is a measurable value, only. The value known as intensity I of light, is proportional to the energy per unit of surface and unit of time. ![]() E = ( A 0) 2 = A.A*, when using the complex representation, *-symbol represents the complex conjugate quantity. When denoting energy transferred by a wave as E, it can be got as square of the amplitude, i.e. Any known detector or recording medium replies only to the incident energy. The frequency of the light wave is too high for any known physical mechanism to reply to the changes of the instantaneous amplitude A. The instantaneous amplitude A, which varies with both, time and space, cannot be measured experimentally in a direct way. When the k( k x, k y, k z) direction is general, the phase in a point determined by a displacement vector r( x, y, z) includes the scalar product of k.r.Ī = A 0 e i Φ = A 0 cos Φ + i A 0 sin Φ E3Īs for light wave recording, one has to realize a special property of light waves. Because of that, wave fronts are parallel planes, perpendicular to the z–axis. to the wave vector k.įor example, considering a wave propagating in the + z direction, the wave vector k is parallel to the z–axis everywhere. It is perpendicular to the direction of propagation, i.e. It is the surface upon which the wave has equal phase. Such a time interval is called period and T = 1/ ν.Ī wave front is another useful term for us, else. It lasts T = λ/c seconds to pass the path λ at the speed c. ω, is angular frequency, which is related to the linear frequency, ν, by the formula ω = 2π ν. The distance between the two neighbouring amplitude peaks of the same kind is wavelength λ. Its absolute value k = 2π/ λ defines the wave number. Where r( x, y, z) is a displacement vector determining a point in a space and k( k x, k y, k z) denotes for a wave vector, determining direction of wave propagation. Modelling light as a light wave A( r, t) depending on space ( r) and time ( t) means, that there are two main parameters – the amplitude A 0 of a wave and its phase ΦĪ = A 0 cos Φ ( r, t ) = A 0 cos ( ω t − k. What does it mean – all the information? Let us repeat some basic terms. The term hologram tells us that all the information transported by light wave is recorded. to create a hologram, the phenomenon of two-wave interference of light is applied. ![]() It is very important, because there are two basic physical light wave phenomena, enabling holography. all the light waves coming from a laser have the same properties. People specialized in photonics, an interdisciplinary field dealing with utilizing photons, may know that holography is closely related to a special kind of light – laser light, which possesses a special property – coherence, i.e. A holographic technology comes along with advertisements, promotions. Well, people today come across the term hologram and can meet holograms on banknotes, various cards and products. Holography will soon be an integral part of the light age of information and communications.“ The use of holograms is the representation of a new visual language in communication and we are moving into the age of light as the media of the future. Next years might bring us to see a new world of holograms in every aspect. Holography has found its applications in almost all industrial sectors including commercial and residential applications. “Since its first commercial usage in the 70’s the demand has only increased with each passing year. It is hard to find its origin, since it can be found at the beginnings of many papers dealing with holography. The image floats in space either behind, in front, or straddling the recording medium.” – is the first one. The image demonstrates complete parallax and depth-of-field. “Holography is the only visual recording and playback process that can record our 3D world on a two-dimensional recording medium and playback the original object or scene to the unaided eyes, as a 3D image. I would like to begin the chapter with two quotations, I came across during my study, I like very much and I am certain, they literally express holography, its properties, its beauty and its role today, at the beginning either of the 21st century or the third millenium, we have an opportunity to be eye witnesses. ![]()
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