In co2 laser, the co2 vibrates when it collides with nitrogen atoms instead of getting excited to next level.Why? why is this vibration after collision is not seen in Helium-neon laser?please explain me

The behavior of CO2 lasers and helium-neon (He-Ne) lasers is different because of the differences in the energy levels of the atoms and molecules involved.

In a CO2 laser, the lasing action occurs due to the vibration of carbon dioxide (CO2) molecules. When a CO2 molecule collides with a nitrogen (N2) molecule, the collision can transfer energy to the CO2 molecule, causing it to vibrate. This vibration leads to the emission of photon particles, which results in laser light. The nitrogen molecule acts as an energy transfer medium in this process.

On the other hand, a He-Ne laser operates based on the excitation of the neon (Ne) atoms instead of molecular vibrations. When an electrical discharge is passed through a mixture of helium (He) and neon gases, electrons collide with neon atoms. These collisions excite the neon atoms, causing them to move to a higher energy level. When these excited neon atoms return to their original energy levels, they emit photons, generating laser light. In this case, the helium gas helps in sustaining the discharge.

The reason why the vibration after collision is not seen in a He-Ne laser is due to the absence of molecules like CO2 in the laser medium. The laser action in a He-Ne laser primarily relies on the excitation and de-excitation of single neon atoms, rather than vibrational motion of molecules.

In summary, the behavior of CO2 lasers and He-Ne lasers is different because of the distinct energy levels and excitation mechanisms involved. CO2 lasers rely on molecular vibrations of CO2 with the assistance of nitrogen as an energy transfer medium, while He-Ne lasers operate based on the excitation of individual neon atoms.