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  2. Helium–neon laser - Wikipedia

    en.wikipedia.org/wiki/Heliumneon_laser

    Schematic diagram of a typical 2-3 mW red (633 nm) heliumneon laser tube Commercial He-Ne lasers are relatively small devices compared to other gas lasers, having cavity lengths usually ranging from 15 to 50 cm (but sometimes up to about 1 meter to achieve the highest powers), and optical output power levels ranging from 0.5 to 50 m W .

  3. List of laser types - Wikipedia

    en.wikipedia.org/wiki/List_of_laser_types

    Laser types with distinct laser lines are shown above the wavelength bar, while below are shown lasers that can emit in a wavelength range. The height of the lines and bars gives an indication of the maximal power/pulse energy commercially available, while the color codifies the type of laser material (see the figure description for details).

  4. File:Helium neon laser spectrum.svg - Wikipedia

    en.wikipedia.org/wiki/File:Helium_neon_laser...

    English: Spectrum of a en:Helium neon laser taken using an Ocean Optics HR2000 spectrometer by bouncing the laser off of a white benchtop and guiding the diffuse reflected light directly into the spectrometer. The emission spectrum of the HeNe laser is even more monochromatic than seen here (it is typically around a mere 2 picometers in ...

  5. Gas laser - Wikipedia

    en.wikipedia.org/wiki/Gas_laser

    The first gas laser, the Heliumneon laser (HeNe), was co-invented by Iranian engineer and scientist Ali Javan and American physicist William R. Bennett, Jr., in 1960. It produced a coherent light beam in the infrared region of the spectrum at 1.15 micrometres. [1] A helium-neon laser is a well-known type of gas laser

  6. 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 heliumneon (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 ...

  7. Resonance Raman spectroscopy - Wikipedia

    en.wikipedia.org/wiki/Resonance_Raman_spectroscopy

    The difference is the choice of the laser wavelength, which must be selected to match the energy of an electronic transition in the sample. A tunable laser is thus often used for resonance Raman spectroscopy, since a single laser can be used to generate many possible excitation wavelengths to match different samples. [8]

  8. Population inversion - Wikipedia

    en.wikipedia.org/wiki/Population_inversion

    A four-level laser energy diagram. Here, there are four energy levels, energies E 1, E 2, E 3, E 4, and populations N 1, N 2, N 3, N 4, respectively. The energies of each level are such that E 1 < E 2 < E 3 < E 4. In this system, the pumping transition P excites the atoms in the ground state (level 1) into the pump band (level 4).

  9. Quantum defect - Wikipedia

    en.wikipedia.org/wiki/Quantum_defect

    The energy difference is lost to heat, which may carry away the excess entropy delivered by the multimode incoherent pump. The quantum defect of a laser can be defined as the part of the energy of the pumping photon which is lost (not turned into photons at the lasing wavelength) in the gain medium during lasing. [1]