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  2. Population inversion - Wikipedia

    en.wikipedia.org/wiki/Population_inversion

    The level 3 is sometimes referred to as the pump level or pump band, and the energy transition E 1 → E 3 as the pump transition, which is shown as the arrow marked P in the diagram on the right. Upon pumping the medium, an appreciable number of atoms will transition to level 3, such that N 3 > 0. To have a medium suitable for laser operation ...

  3. Optical pumping - Wikipedia

    en.wikipedia.org/wiki/Optical_pumping

    Optical pumping is a process in which light is used to raise (or "pump") electrons from a lower energy level in an atom or molecule to a higher one. It is commonly used in laser construction to pump the active laser medium so as to achieve population inversion. The technique was developed by the 1966 Nobel Prize winner Alfred Kastler in the ...

  4. Laser pumping - Wikipedia

    en.wikipedia.org/wiki/Laser_pumping

    Laser pumping is the act of energy transfer from an external source into the gain medium of a laser. The energy is absorbed in the medium, producing excited states in its atoms. When for a period of time the number of particles in one excited state exceeds the number of particles in the ground state or a less-excited state, population inversion ...

  5. Laser construction - Wikipedia

    en.wikipedia.org/wiki/Laser_construction

    The type of pump source used principally depends on the gain medium, and this also determines how the energy is transmitted to the medium. A helium–neon (HeNe) laser uses an electrical discharge in the helium-neon gas mixture, a Nd:YAG laser uses either light focused from a xenon flash lamp or diode lasers , and excimer lasers use a chemical ...

  6. Sisyphus cooling - Wikipedia

    en.wikipedia.org/wiki/Sisyphus_cooling

    Sisyphus cooling can be achieved by shining two counter-propagating laser beams with orthogonal polarization onto an atom sample. Atoms moving through the potential landscape along the direction of the standing wave lose kinetic energy as they move to a potential maximum, at which point optical pumping moves them back to a lower energy state, thus lowering the total energy of the atom.

  7. Ruby laser - Wikipedia

    en.wikipedia.org/wiki/Ruby_laser

    The ruby laser is a three level solid state laser. The active laser medium (laser gain/amplification medium) is a synthetic ruby rod that is energized through optical pumping, typically by a xenon flashtube. Ruby has very broad and powerful absorption bands in the visual spectrum, at 400 and 550 nm, and a very long fluorescence lifetime of 3 ...

  8. Laser - Wikipedia

    en.wikipedia.org/wiki/Laser

    The device was only capable of pulsed operation, due to its three-level pumping design scheme. Later that year, the Iranian physicist Ali Javan , and William R. Bennett Jr. , and Donald R. Herriott , constructed the first gas laser , using helium and neon that was capable of continuous operation in the infrared (U.S. Patent 3,149,290); later ...

  9. Four-wave mixing - Wikipedia

    en.wikipedia.org/wiki/Four-wave_mixing

    Four-wave mixing (FWM) is an intermodulation phenomenon in nonlinear optics, whereby interactions between two or three wavelengths produce two or one new wavelengths. It is similar to the third-order intercept point in electrical systems. Four-wave mixing can be compared to the intermodulation distortion in standard