The working principle and structure of electrically excited cross-flow co2 laser tube.
The gain medium volume of cross-flow co2 laser tube is large,The output beam is mainly multiple mode. Obtained the lower-order mode laser via adding diameter L light path or using folded cavity.Improving the beam quality, can adapt to various needs.
The working principle of cross-flow co2 laser tube
Cross-flow co2 laser tube electrode plus dc voltage produces glow discharge.The working gas flow direction,discharge direction and optical axis direction of cross-flow co2 laser tube are three-axis orthogonal.Fan driven mixed working gas transversely passing the discharge electrode area,gas fast flow and adopts a multi-plate electrode structure.To obtain a large volume, uniform and stable glow discharge.This discharge causes the CO2 molecules to vibrate, creating transitions between energy levels, and achieving population inversion.
Generated stimulated radiation as particles transition from high to low energy levels,Oscillation by back and forth reflection between resonator mirrors and outputting the laser through the output mirror.
Co2 molecular consist of three atoms arranged linearly and symmetrically.Three atoms in a straight line,carbon in the middle, oxygen on both sides.as 2.1.1（a） shown in the figure:
There are three basic vibration modes:
(b)Symmetrical vibration——Two oxygen atoms vibrate along the axis of symmetry along the opposite or opposite carbon atoms,carbon atoms remain motionless.
(c)Deformation vibration——Three original vertical symmetry axis vibrations,and the direction of movement of the carbon atoms is opposite to the direction of movement of the two oxygen atoms.
(d)Antisymmetric vibration——Three atoms vibrate along the axis of symmetry,the direction of movement of carbon atoms is opposite to the direction of movement of two oxygen atoms.The laser line of Co2 laser tube is generated by a transition between molecular vibrational levels.
The laser tube excites CO2 molecules up to level 000 1 by electrical excitation.Later,the co2 molecule jumps from the upper to the lower levels 10 and 020.Release Co2 laser 10.6f'm and 9.6 F/rrl.Among them, 9.6) um laser is suppressed due to competitive effects.And the 10.6 t/m laser is amplified by the cavity.Outputting laser co2 molecules through the output mirror can generate particle number inversion by direct electronic excitation,But the gain is less.After joining N2,since the y-1 level of the N2 molecule is similar to the height of the 0001 level of the C09 molecule.Therefore, resonance transfer of energy occurs in a device that is continuously operated at a low pressure or a high-pressure pulse.
After the energy resonance is transferred, the energy can be efficiently transferred to the co2 laser molecule.Therefore, the gain and output power of the CO 2 laser can be significantly improved.In the C02 laser, adding He or Ar improves the heat resistance.Because the thermal conductivity of He or Ar is an order of magnitude higher than C02 and N2.At the same time, He can increase the relaxation rate of the laser level 1000 and improve the laser efficiency and power.
