Gas laser: description, characteristics, principle of operation

The main working component of any laser device is the so-called active medium. It not only acts as a source of directed flow, but in some cases it can significantly strengthen it. This is precisely the feature of gas mixtures that act as active substances in laser installations. In this case, there are different models of similar devices, differing in both the design and the characteristics of the working environment. One way or another, a gas laser has many advantages that have allowed it to take a firm place in the arsenal of many industrial enterprises.

Features of the gas environment

Traditionally, lasers are associated with solid and liquid media that promote the formation of a light beam with the necessary performance characteristics. The gas has advantages in the form of homogeneity and low density. These qualities allow the laser flow not to be distorted, not to lose energy and not to dissipate. Also, the gas laser is distinguished by an increased radiation direction, the limit of which is determined only by the diffraction of light. Compared to solid bodies, the interaction of gas particles occurs exclusively in collisions under conditions of thermal displacement. As a result, the energy spectrum of the filler corresponds to the energy level of each particle separately.

The device of gas lasers

The classical device of such devices is formed by a sealed tube with a gaseous functional medium, and also an optical resonator. The discharge tube is usually made of corundum ceramics. It is placed between the reflecting prism and the mirror on the beryllium cylinder. The discharge is performed in two sections with a common cathode at constant current. Oxidantanthal cold cathodes are most often divided into two parts by means of a dielectric gasket, which ensures uniform distribution of currents. Also, the device of the gas laser provides the presence of anodes - their function is performed by stainless steel, represented in the form of vacuum bellows. These elements provide a movable connection of tubes, prisms and mirror holders.

Principle of operation

To fill the energy of the active body in the gas, electric discharges are applied, which are produced by the electrodes in the cavity of the instrument tube. During the collision of electrons with gas particles, they are excited. Thus, the basis for photon emission is created. Forced emission of light waves in the tube increases during their passage through the gas plasma. The exposed mirrors on the ends of the cylinder form the basis for the predominant direction of the light flux. A semi-transparent mirror, which is supplied with a gas laser, takes a fraction of the photons out of the directed beam, and the rest of them is reflected inside the tube, supporting the radiation function.

Characteristics

The internal diameter of the discharge tube is usually 1.5 mm. The diameter of the oxide-tantalum cathode can reach 48 mm with a length of 51 mm. The design operates under the influence of a direct current with a voltage of 1000 V. In helium-neon lasers, the radiation power is small and, as a rule, is calculated in tenths of W.

Models on carbon dioxide assume the use of tubes with a diameter of 2 to 10 cm. It is noteworthy that a gas laser operating in a continuous mode has very high power. From the point of view of operational efficiency, this factor sometimes goes into a plus, however, in order to maintain the stable function of such devices, durable and reliable mirrors with increased optical properties are required. As a rule, technologists use metal and sapphire elements with gold processing.

Varieties of lasers

The main classification implies the separation of such lasers by the type of gas mixture. The features of models on a carbon dioxide active body have already been mentioned, but ionic, helium-neon, and chemical media are also common. For the construction of the device, ion gas lasers require the use of materials with high thermal conductivity. In particular, metal-ceramic elements and details based on beryllium ceramics are used. Helium-neon media can operate at different wavelengths in terms of infrared radiation and in the spectrum of visible light. Mirrors of the resonator of such devices are distinguished by the presence of multilayer dielectric coatings.

Chemical lasers represent a separate category of gas tubes. They also assume the use of gas mixtures as the working medium, but the process of formation of light radiation is provided by a chemical reaction. That is, the gas is used for chemical excitation. Devices of this type are advantageous in that direct conversion of chemical energy into electromagnetic radiation is possible in them.

Application of gas lasers

Virtually all lasers of this type are distinguished by a high degree of reliability, durability and an affordable price. These factors have caused their wide distribution in different branches. For example, helium-neon devices have found application in leveling and alignment operations, which are performed in mining, shipbuilding, and also in the construction of various structures. In addition, the characteristics of helium-neon lasers are suitable for use in the organization of optical communications, in the development of holographic materials and quantum gyroscopes. The argon gas laser, whose application shows efficiency in the processing of materials, was no exception in terms of practical utility. In particular, such devices serve as a carver of hard rocks and metals.

Reviews of gas lasers

If we consider lasers in terms of advantageous operational properties, then many users note the high directivity and overall quality of the light beam. Such characteristics can be explained by a small fraction of the optical distortions, regardless of the ambient temperature conditions. As for the shortcomings, a great deal of tension is needed to unlock the potential of gas media. In addition, a helium-neon gas laser and devices operating on the basis of carbon dioxide mixtures require the connection of considerable electrical power. But, as practice shows, the result justifies itself. The application finds both low-power apparatuses and instruments with a large force potential.

Conclusion

The possibilities of gas-discharge mixtures in terms of their application in laser installations have not yet been sufficiently developed. Nevertheless, the demand for such equipment has long and successfully grown, forming an appropriate niche in the market. The gas laser was most widely used in industry. It is used as a tool for point and accurate cutting of solid materials. But there are factors holding back the distribution of such equipment. Firstly, it is a rapid wear of the element base, which reduces the longevity of the instruments. Secondly, there are high requirements for ensuring the electrical discharge necessary for beam formation.