Actually two level scheme has serious difficulty. In two level upward (level 1 to 2)transition and downward transitions(2 to 1) occurs. In steady state, the population inversion not obtain. (population inversion Means the numbers of atom at level 2 is greater than level 1)
A laser emits a beam of energy in the form of light. But to get energy out of a laser, we have to put some in. Depending on the type of laser, there are different ways to do this. What is important here is that the energy put into the lasing medium, the energy that is pumped into that medium to stimulate it, to excite it (the actual term), to induce it to lase, is supplied by an outside source, by a pump appropriate to that type of laser. So the pump, that thing outside the medium that stimulates it to induce it into lasing, is pumping when it is exciting the medium. Hope this was, um, coherent....
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
Three and Four Level Laser SchemesWe have said that the two level scheme is not generally feasible for laser action. There are two main reasons for this. The first reason is that the energy being used to pump the particles into the upper laser state has an equal probability of stimulating them back down. Thus it is not possible to get nore than half of the particles into the excited state. The three level scheme gets around this problem by first exciting the particles to an excited state higher in energy than the upper laser state.(See figure below) The particles then quickly decay down into the upper laser state. It is important for the pumped state to have a short lifetime for spontaneous emission compared to the upper laser state. The upper laser state should have as long a lifetime (for spontaneous emission) as possible, so that the particles live long enough to be stimulated and thus contribute to the gain.The four level laser scheme goes one step further and also depopulates the lower laser level by a fast decay process.(see figure below) This greatly decreases the loss of laser photons (v2) by stimulated absorption processes since the particles in the lower laser level have a short life-time for spontaneous emission.
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A laser, by its very action of amplification of light, tends to be monochromatic. (one colour). But lasers may be made in several different colours depending on the materials used.
by pumping electrons to higher energy orbitals.
A laser emits a beam of energy in the form of light. But to get energy out of a laser, we have to put some in. Depending on the type of laser, there are different ways to do this. What is important here is that the energy put into the lasing medium, the energy that is pumped into that medium to stimulate it, to excite it (the actual term), to induce it to lase, is supplied by an outside source, by a pump appropriate to that type of laser. So the pump, that thing outside the medium that stimulates it to induce it into lasing, is pumping when it is exciting the medium. Hope this was, um, coherent....
Ans. Optical pumping methods are very ineffective for gas lasers because gas atomsshow sharp energy, levels as compared to solids, which are characterized by energy bands raTher than energy levels. Thus for gas laser the electrical discharge is used for pumping.
Dieter Suter has written: 'The physics of laser-atom interactions' -- subject(s): Optical pumping, Laser manipulation (Nuclear physics), Laser spectroscopy
OKI does manufacture laser printers suitable for home use as well as commercial use. Their home laser printers are just as great as the commercial ones.
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
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.
This is kirit vaghela, The answer for the above question is that as far as ruby laser is concerned the pupmping is used is nothing but it is completed by optical pupmping.
population inversion is very very important for laser action...... i know you have talant to explain it....
to increase the wavelength of the beam and increase the laser action
Three and Four Level Laser SchemesWe have said that the two level scheme is not generally feasible for laser action. There are two main reasons for this. The first reason is that the energy being used to pump the particles into the upper laser state has an equal probability of stimulating them back down. Thus it is not possible to get nore than half of the particles into the excited state. The three level scheme gets around this problem by first exciting the particles to an excited state higher in energy than the upper laser state.(See figure below) The particles then quickly decay down into the upper laser state. It is important for the pumped state to have a short lifetime for spontaneous emission compared to the upper laser state. The upper laser state should have as long a lifetime (for spontaneous emission) as possible, so that the particles live long enough to be stimulated and thus contribute to the gain.The four level laser scheme goes one step further and also depopulates the lower laser level by a fast decay process.(see figure below) This greatly decreases the loss of laser photons (v2) by stimulated absorption processes since the particles in the lower laser level have a short life-time for spontaneous emission.
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.