Matrix and types of matrices➨➨
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THE RUBY LASER-A PULSED LASER It is the first working laser developed by maiman in 1960. it is a solid stat laser and makes use of the three level scheme of population inversion . It consists of three essential parts: 1. The working material: the working material is a ruby crystal which belongs to a family of gems. actually it is aluminium oxide (Al₂O₃) doped with 0.05% chromium oxide (Cr₂O₃).Thus some of the aluminium atom in the crystal lattice are replaced by Cr++ion which give ruby a pink colour. The resonant cavity: It is a specially prepared ruby cylinder in which light intensity can be build up by multiple reflection. For this purpose a ruby laser 20 to 30 cm. and 0.5 to 2 cm in diameter is grown. the crystal is cut polished, so that the ends are flat and parallel, with the end planes perpendicular to the axis of rod. 2.The optical pumping system: The optical pumping is done by an external source. in general ,a helical xenon flash tube acts as a pump
LASER SYSTEM FULL FORM OF LASER L→Light A→Amplification by S→Stimulated E→Emission of R→Radiation Laser began to be developed in 1958. However, the first laser was fabricated by maiman in 1960. it is a device for producing very intense, almost unidirectional,monochromatic and coherent visible light beams. Spontaneous Emission￫ When an atom in an excited state E2 falls to the ground state E1 by spontaneous emitting a photon of frequency ʋ=E2-E1/h, the process is known as spontaneous emission and has been show in fig .(a). Stimulated or Induced Emission￫ When a photon of frequency exactly equal to ʋ=E2-E1/h is incident on the atom in excited state E2,then it in