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 enhance it. It is precisely this feature that gas mixtures acting as the active substance in laser installations possess. At the same time, there are different models of such devices, which differ in design and characteristics of the working environment. One way or another, a gas laser has many advantages that allowed it to occupy a solid place in the arsenal of many industrial enterprises.
Features of the action of the gas medium
Traditionally, lasers are associated with solid-state and liquid media that contribute to the formation of a light beam with the necessary performance characteristics. At the same time, gas has advantages in the form of uniformity and low density. These qualities allow the laser stream not to be distorted, not to lose energy and not to disperse. Also, a gas laser is characterized by an increased directivity of radiation, the limit of which is determined only by light diffraction. Compared to solids, 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 individually.
Gas laser device
The classic device of such devices is formed by a sealed tube with a gaseous functional medium, as well as an optical resonator. The discharge tube is usually made of corundum ceramic. It is placed between the reflective prism and the mirror on the beryllium cylinder. The discharge is carried out in two sections with a common cathode at constant current. Tantalum cold cathodes are most often divided into two parts by means of a dielectric strip, which ensures uniform distribution of currents. Also, the gas laser device provides for the presence of anodes - their function is performed by stainless steel, presented 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 a gas, electric discharges are used , which are generated by electrodes in the cavity of the device’s tube. In the process of collision of electrons with gas particles, their excitation occurs. Thus, the basis for the emission of photons is created. The stimulated emission of light waves in the tube increases as they travel through the gas plasma. Exposed mirrors at the ends of the cylinder create the basis for the predominant direction of the light flux. The translucent mirror with which the gas laser is supplied selects a fraction of the photons from the directional beam, and the rest of them are reflected inside the tube, supporting the radiation function.
Specifications
The inner diameter of the discharge tube is usually 1.5 mm. The diameter of the tantalum oxide cathode can reach 48 mm with an element length of 51 mm. In this case, the design operates under the influence of 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 watts.
Carbon dioxide models suggest 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 a very high power. From the point of view of operational efficiency, this factor is sometimes a plus, however, to maintain the stable function of such devices, durable and reliable mirrors with enhanced optical properties are required. As a rule, technologists use metal and sapphire elements with gold processing.
Varieties of lasers
The main classification involves the separation of such lasers by type of gas mixture. The features of carbon dioxide active body models have already been mentioned, but ionic, helium-neon and chemical media are also common. To fabricate the design of the device, ion gas lasers require the use of materials with high thermal conductivity. In particular, cermet elements and parts based on beryllium ceramics are used. Helium-neon media can operate at different wavelengths according to infrared radiation and in the spectrum of visible light. The resonator mirrors of such devices are characterized by the presence of multilayer dielectric coatings.
Chemical lasers represent a separate category of gas tubes. They also suggest the use of gas mixtures as a working medium, but the process of formation of light radiation is provided by a chemical reaction. That is, gas is used for chemical excitation. Devices of this type are advantageous in that a direct transition of chemical energy into electromagnetic radiation is possible in them.
The use of gas lasers
Almost all lasers of this type are characterized by a high degree of reliability, durability and affordable price. These factors led to their widespread distribution in various industries. For example, helium-neon devices are used in leveling and adjustment operations, which are performed in mine work, in shipbuilding, as well as in the construction of various structures. In addition, the characteristics of helium-neon lasers are suitable for use in organizing optical communications, in the development of holographic materials and quantum gyroscopes. An argon gas laser, the use of which shows efficiency in the field of processing materials, was no exception in terms of practical benefits. In particular, such devices serve as a cutter of hard rocks and metals.
Gas Laser Reviews
If we consider lasers from the point of view of favorable 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 optical distortions, regardless of the ambient temperature conditions. As for the shortcomings, a lot of voltage is needed to unlock the potential of gas media. In addition, a helium-neon gas laser and devices based on carbon dioxide mixtures require the connection of considerable electrical power. But, as practice shows, the result justifies itself. Both low-power devices and devices with high power potential are used.
Conclusion
The possibilities of gas-discharge mixtures in terms of their application in laser systems have not yet been sufficiently developed. Nevertheless, the demand for such equipment has been growing successfully for a long time, forming a corresponding niche in the market. The most common gas laser received in the industry. It is used as a tool for precise and precise cutting of solid materials. But there are also factors holding back the spread of such equipment. Firstly, it is the rapid wear of the elemental base, which reduces the durability of the devices. Secondly, there are high requirements for ensuring the electric discharge necessary for beam formation.