Understanding Atom Excitation in He-Ne Lasers

[paramahamsa]

hello every one
The thing I can't understand is 1) In He-Ne laser the He atoms in the excited state interact with the Ne atoms in the ground state how it is possible?

2) In all the textbooks they wrote that "atoms exite". Wil the atoms exite or the electrons? because to my knowledge atom consists of Nucleus which is heavy.

 

[Integral]

Atoms consist of a nucleus surrounded by a cloud of electrons.

For a laser to work you need to create a population inversion. This mean that you have a large population of atoms with electrons in a particular excited state. These excited state electrons are then caused to drop to a lower energy state simultaenously. The energy released in this state change becomes your laser beam.

 

[paramahamsa]

thks mr integral

 

[Claude Bile]

hello every one
The thing I can't understand is 1) In He-Ne laser the He atoms in the excited state interact with the Ne atoms in the ground state how it is possible?

Via collisions. One atom bumps into another and an energy exchange takes place.

2) In all the textbooks they wrote that "atoms exite". Wil the atoms exite or the electrons? because to my knowledge atom consists of Nucleus which is heavy.

The atoms excite. This is because the discrete energy levels we observe are characteristic of the ATOM and not the subatomic particles that make up the atom. This is why Hydrogen has a different spectrum to Helium for example, despite the fact the both comprise of a nucleus surrounded by electrons.