What are the advantages and disadvantages of He-Ne laser?

He-ne laser is one of the earliest, most mature and most widely used lasers. The gas yard has a definite energy level structure, which is stimulated by external electrons to generate energy level transition and emit laser by stimulated radiation. Therefore, the wavelength of He-Ne laser is pure monolor light with extremely narrow line width and wavelength error of only a few nanometers, and has a great coherence length. Some lasers that emit light by band transition (such as the monochromatic and coherent properties of LD) cannot be compared. The atomic level structure is determined, so the laser is not affected by temperature fluctuations. In addition, the resonator ensures that the laser output has good collimation, and the divergence Angle is only a few arcans. In the need of good monochromatic light, coherence and collimation, especially in the field of precision measurement, gas laser has an unshakable position.

The main disadvantage of He-Ne laser is that it needs high voltage DC power supply, requires higher technical content, and costs more than LD.