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Helium–neon laser at the University of Chemnitz, Germany. A helium–neon laser or He–Ne laser is a type of gas laser whose high energetic gain medium consists of a mixture of helium and neon (ratio between 5:1 and 20:1) at a total pressure of approximately 1 Torr (133 Pa) inside a small electrical discharge.
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).
The first gas laser, the Helium–neon 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
For example, a typical helium–neon laser has a gain bandwidth of about 1.5 GHz (a wavelength range of about 0.002 nm at a central wavelength of 633 nm), whereas a titanium-doped sapphire (Ti:sapphire) solid-state laser has a bandwidth of about 128 THz (a 300 nm wavelength range centered at 800 nm).
A helium–neon laser demonstration. The glow running through the center of the tube is an electric discharge. This glowing plasma is the gain medium for the laser. The laser produces a tiny, intense spot on the screen to the right. The center of the spot appears white because the image is overexposed there. Spectrum of a helium–neon laser.
The first gas laser, using a mixture of helium and neon, was demonstrated in 1960 and emitted radiation at a wavelength of 1.15 μm (infrared range). [2] Two years later, White, together with Dane Rigden, showed that a helium-neon laser can emit radiation at a wavelength of 632.8 nm, i.e., in the visible range of the spectrum. [3]
Most lasers emit light of a very narrow bandwidth, and often provide a suitable light source. A helium–neon laser emits light at 632 nanometres (red), while a frequency doubled Nd:YAG laser emits light at 532 nm (green). Various laser diodes and diode-pumped solid-state lasers emit light in red, yellow, green, blue or violet.
The exact chemical configuration of the dye molecules determines the operation wavelength of the dye laser. Gases, such as carbon dioxide, argon, krypton and mixtures such as helium–neon. These lasers are often pumped by electrical discharge. Solids, such as crystals and glasses.