Why He-Ne tube is narrow ?
The resonant cavity's
a) cross-sectional dimensions governs Transverse mode
b) axial dimensions governs Longitudinal mode
c) The desired TEM00 mode (it gives beam of Gaussian-profile, having minimum spread due to diffraction) is obtained by making cross-sectional dimensions just slightly larger than the spot size of the TEM00 mode.
d) The coexistence of multiple modes reduces the monochromaticity of the laser.
purple
say" ne cell"
Gago patakla ka ne
a railway track has a little distance maintained between the two rails,this is so 'cause during summer they expand and if they don't have distance maintained they bulge causing train accidents and during winter they contract causing the rails to snap
Apart from symbols taken from their ancient names (like Ag for Silver - from Argentum, and K for potassium from Kalium) almost all other symbols are taken from the element's name - the first letter and, where necessary, another letter too - usually the next one. So C is Carbon, but when Calcium was discovered, it could not be give the symbol C as well, so it was given the symbol Ca. In the same way Hydrogen has the symbol H, but Helium cannot be given the symbol H too, so it has the symbol He, being the first two letters of its name. If there are two elements with the same two first letters (like magnesium and manganese) then another two letters are chosen instead - in this case the first and third letters rather than the first two - making the symbol of magnesium Mg, and that of manganese Mn. Similarly, for neon, N is the symbol for Nitrogen, and so Ne was chosen for Neon, being the first two letters of the name.
The old laser printers used He-Ne laser , and the modern laser printers use infrared laser .
The typical ratio of helium (He) to neon (Ne) in a helium-neon (He-Ne) laser is around 5:1, meaning there is approximately five times more helium than neon in the laser tube. Helium serves as the primary energy source while neon provides the lasing action to produce the laser light.
1.he-ne laser is gaseous state. Ruby is solid state laser. 2.he-ne laser requires electrical pumping. ruby laser requires optical pumping. 3.he-ne laser has 4 energy levels. ruby has 3 energy level. 4.he-ne laser gives continuous output. ruby laser gives output in form of pulse 5. he-ne laser is cheaper
he ne laser has emmisions due to atleast three diffrent levels leading to three diffrent wavelenght of photons emitted..also as opposed to ruby laser which uses xenon flash tube , which gets highly heated and cant be used continously to exite the elctrons , a he-ne laser uses a high potential source like a tesla coil wich can be used continuously..
1.Nd YAG LASER 2.he-ne laser 3.co2 laser 4.semi condector laser(homo,hetrojunction) 5.diode laser etc.............
Helium gas serves as the active medium in a He-Ne laser. It provides population inversion between energy levels, allowing for laser action. The helium gas helps to excited the neon atoms to produce laser light at a wavelength of 632.8 nm.
Mirrors are used in ruby and He-Ne lasers to create an optical resonator cavity for the laser to oscillate and produce coherent light. The mirrors reflect the emitted light back and forth within the cavity, amplifying the light through stimulated emission process. This process helps to establish the necessary conditions for laser action, where the light waves are aligned and reinforced to produce a powerful coherent beam.
The value of the thickness of wire using a He-Ne laser can be determined by measuring the interference pattern produced when the laser light is reflected off the wire. By analyzing this interference pattern, the thickness of the wire can be calculated based on the wavelength of the laser light and the angles at which the interference occurs.
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Helium neon laser is better than ruby laser or most of the four level lasers are better than three level lasers due to the following reasons: The laser output is continuous in the case of helium-neon laser. But it is in the form of pulse in the ruby laser. Ruby laser requires high power pumping source, whereas Helium-neon laser requires low power pumping source like electric discharge. Efficiency of helium-neon laser is more than ruby laser. The defects due to crystalline imperfections are also present in the ruby laser. But it is not so in the helium-neon laser.
because of gas in active center Neon gas worked as Active Center for He-Ne laser.to accelerate the Ne atoms very high and efficient Pumping is required. Which can only be given by Electric Discharge Pumping.
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