CO2 laser marking machine is an important gas laser. It has some outstanding advantages:
① Large output power and high energy conversion efficiency. The general closed tube CO2 laser marking machine can have tens of watts of continuous output power, which is far more than other gas lasers; The transverse flow electrically excited C02 laser can have several hundred thousand watts of continuous output. The energy conversion efficiency of CO2 laser can reach 30%-40%, which is also higher than that of general gas laser.
② It makes use of the transition between vibrational and rotational energy levels of CO2 molecules, and has relatively rich spectral lines at 10 μ There are ten spectral lines near M. The high-pressure CO2 laser discovered in recent years can even achieve μ m-10 μ Continuously tunable output between M.
③ Its output band is just the atmospheric window (that is, the atmosphere is more transparent to this wavelength). In addition, it has the advantages of high optical quality, good coherence, narrow linewidth and stable operation. Therefore, it has many applications in the national economy and national defense, such as processing (welding, cutting, drilling, etc.), communication, radar, chemical analysis, laser-induced chemical reaction, surgery, etc.
The working principle and stimulated emission process of CO2 laser are complex. There are three different movements of molecules. One is the movement of electrons in the molecule, which determines the electronic energy state of the molecule; The second is the vibrational motion of atoms in molecules, that is, atoms in molecules vibrate periodically around their equilibrium positions and determine the vibrational energy states of molecules; The third is molecular rotation, that is, the molecule as a whole rotates continuously in space. This movement of the molecule determines the rotational energy state of the molecule. Molecular motion is extremely complex, so the energy levels are also very complex.
CO2 molecule is a linear symmetric molecule, with two oxygen atoms on both sides of the carbon atom, indicating the equilibrium position of the atom. The atoms in the molecule are always in motion and must vibrate around their equilibrium positions.