Substances composed of molecules, the molecules are composed of atoms. In fact, the atom is not composed of the smallest particles of the substance, which is composed of nuclei and nuclear rotation around a group of electronic micro-systems. The rotation of the orbit is a set of concentric park space. The concentric Park, a limited number of allowed outside the orbit of the other tracks do not allow the electronics exist.
Atoms with internal energy, the size of the internal energy can not be continuously changing, step by step separate. This separation of energy called energy levels. Electronics in which the state determines the energy level high and low. Under normal circumstances, the electronic is always located in the inner orbit, this state is called the ground state or steady state. Always the vast majority of electronic group in the ground state atomic system. No external force, the inner electrons do not run up the outer layer. In other words, low energy level of electrons do not automatically went to the high energy level up.
To be external when the electronic ground state with the appropriate way to give a certain energy, such as light, electron impact, chemical action or heat, etc., will be excited to high energy level up. Contrary electronic atom s own internal contradictions, will spontaneously return to the low-level energy level up, a process called spontaneous transition. Transition refers to the micro-particle system to do a state transition from a particular state. Spontaneous transition of the internal energy of the atom is reduced, the excess energy will be released. The release of two forms, one hot, one is light. Called non-radiative transition to the heat, light called spontaneous radiative transition, the radiation that the spontaneous emission, the general light source such as lamp light spontaneous transition.
Of each atom in the atomic group outermost electron eclectic, radioactive materials may also contain a wide array of elements. Each atomic electronic orbital semi-major does not equal the energy difference between the energy levels are not the same. Electromagnetic radiation by atoms Group, the intensity of each mode, frequency, phase, direction may be vastly different, so the spontaneous emission in optics called non-coherent light. Fluorescent lamp radiation are non-coherent light, light and radio waves, microwaves, a form of electromagnetic energy, although the effect of electromagnetic radiation with frequency, but the essence of all the radiation processes are the same.
The generation of laser is the use of substances called by the stimulated emission characteristics of all electronic material not subject to external energy excitation kibbutz in the ground state level A by the outside world energy excitations, part of the electronics will rise to the energy level of the level of B, then they will soon be the form of fluorescent transitions, decline to level C material. The residence time of the electrons in the highest level by stimulation is very short, about 10 to the minus eight s. But some substances when the electronic transition to the high energy level can stay longer. Such as the ruby ??chromium ion will be able to stay a few milliseconds, and thus where the formation of a stable residence status (metastable).
Electrons from the metastable further transition to the low energy level, a photon. If the photons in the optical resonator (at both ends of a cavity mirror), reflected back, it will induce the transition of the same nature, resulting in the same frequency with the phase of the photon. Evoked the role of these two photons will resurgence, it goes on the same frequency will produce a strong enough, with the phase of light shot out from the optical resonator has a semipermeable mirror, which is stimulated emission.
Subject to repeated stimulated emission of light by multiple resonant cavity feedback, enlarge and form a bunch of the same frequency and same phase in the same direction, a strong optical flow, from the semi-inverse semi-permeable lenses in the injection, which is a laser.
Born in 1900 the Hungary Englishman Gabor (DGabor,) invention of holography, for which he obtained in 1971 the Nobel Prize. 1962 the enforcement University of secret security Leith (ENLeith), and the the upa Turk Nice (Jvpatnicks,) using laser capture success of the first practical hologram, ie off-axis-type two-beam holographic picture. Holography, the English name called: "Holography" for the Greek, meaning all records that record all the information – amplitude and phase. Can reproduce the entire object as the use of any district in the hologram laser photography. Therefore, as long as a small part of the debris to save the film will be able to reproduce the original all the scenery, which is the source of holography is usually understood as all the information.