When light of suitable frequency incident on the substance, the atom of the substance go to the excited states by absorbing this light. The atom in the excited state come to the ground state or lower energy state by the emission of light or electromagnetic radiation. Einstein predicted that the emission of light or electromagnetic … Read more
Coherence is the term used to describe the phase correlation phenomenon between two waves with respect to time or space. Temporal Coherence Temporal coherence is the correlation between the electric field at a point in the space at time t₁ [i.e. E (x, y, z, 1₁)]and the electric field at the same point at time … Read more
The term Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. There are main 3 components of Laser device: The active Medium or laser gain medium. A pumping device. A resonant cavity. COMPONENTS OF LASER The basic laser components are active or gain medium, pumping device or source and resonant cavity is … Read more
Before study the properties of photon we must have to know some basic introduction of photon. In 1905, Einstein explained photoelectric effect by considering light consisted of quantum of energy E = hv, Where v is the frequency of the radiation and h=6.63*10-34 Js is Planck’s constant. Gilbert Lewis (an American chemist) in 1926 coined … Read more
Co2 Laser beam is an intense, monochromatic, concentrated, and coherent beam of light. Co2 laser has a wavelength of output is 0.6μm and 10.6μm and the power output of Co2 laser is about 10kW. It can be focused on a very small area. And hence the laser generates very high intensity in the area of … Read more
In an Ordinary photograph of an object taken by a camera three-dimensional scenes is recorded as a two-dimensional scene. Since the emulsion on the photographic plate is sensitive to intensity variations only. Therefore, the photograph records only the intensity distribution in a certain plane. In ordinary photographs, the phase distribution that prevailed at the plane … Read more
In dye laser, organic dyes are used as an active medium. Organic dyes are colored substances having the ability to impart colors to liquids, gases, and solid. Examples of organic dye molecules are rhodamine 6G (Xanthene dye), Coumarin, oxazines, anthracenes, etc. Although organic dye molecules are very large, only the small part of the molecule … Read more
In a molecular gas laser, laser action is achieved by transitions between vibrational and rotational levels of molecules. Its construction is simple and the output of this laser is continuous. In the Co2 molecular gas laser, the transition takes place between the vibrational states of Carbon dioxide molecules. Carbon Dioxide Laser: Definition, Principle Definition In carbon … Read more
Excimer Laser An excimer laser is the type of molecular laser – Isolated atoms and ions in ionic laser have discrete energy levels. However, molecules have energy bands. These bands have electronic, vibrational, and rotational energy levels. Each electronic energy level has a large number of vibrational energy levels and each vibrational level has a … Read more
In nitrogen laser, active or gain or lasing medium is nitrogen molecules in the gaseous phase. It is a three-level laser. Population inversion in nitrogen laser is achieved by an electrical pumping source. Normally, pumping is provided by direct electron impact. Construction and Working of Nitrogen Laser The Active Medium ( or Nitrogen laser gain … Read more