in a He-Ne laster, the laster transition takes place in

Hii,

A helium–neon laser or He-Ne laser, is a type of gas laser whose gain medium consists of a mixture of 90% helium and 10% neon at a total pressure of about 1 torr inside of a small electrical discharge.

In helium-neon lasers , we use high voltage DC as the pump source.

A high voltage DC produces energetic electrons that travel through the gas mixture.

The gas mixture in helium-neon laser is mostly comprised of helium atoms.

Therefore, helium atoms observe most of the energy supplied by the high voltage DC.

In transition in He - Ne laser , an electric discharge in gas pumps the helium atom to higher energy states (which is metastable state ≈10−8s ).

Hope this will help you,

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