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 can significantly enhance it. It is precisely this feature that gas mixtures that act as an active substance in laser installations have. At the same time, there are different models of such devices, which differ both in design and in the characteristics of the working environment. One way or another, the gas laser has many advantages that have allowed it to take a strong place in the arsenal of many industrial enterprises.
Features of the action of the gas medium
Traditionally, lasers are associated with solid and liquid media that contribute to the formation of a light beam with the required performance. In this case, the gas has the advantages of uniformity and low density. These qualitiesallow the laser beam not to be distorted, not to lose energy and not to scatter. Also, the gas laser is characterized by an increased directivity of radiation, the limit of which is determined only by the diffraction of light. Compared to solids, the interaction of gas particles occurs exclusively during collisions under conditions of thermal displacement. As a result, the energy spectrum of the filler corresponds to the energy level of each particle separately.
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 a reflecting prism and a mirror on a beryllium cylinder. The discharge is performed in two sections with a common cathode at direct current. Tantalum oxide cold cathodes are most often divided into two parts by means of a dielectric spacer, 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 flexible connection between tubes, prism and mirror holders.
Working principle
To fill the active body in gas with energy, electric discharges are used, which are generated by electrodes in the cavity of the device tube. During the collision of electrons with gas particlesthey are aroused. This creates the basis for the emission of photons. The stimulated emission of light waves in the tube increases as they pass through the gas plasma. The exposed mirrors at the ends of the cylinder form the basis for the preferential direction of the light flux. A translucent mirror, which is supplied with a gas laser, selects a fraction of photons from the directional beam, and the rest of them are reflected inside the tube, maintaining the radiation function.
Features
The inner diameter of the discharge tube is usually 1.5mm. 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 action 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 a W.
Carbon dioxide models use tubes with a diameter of 2 to 10 cm. It is noteworthy that a gas laser operating in continuous mode has a very high power. From the point of view of operational efficiency, this factor is sometimes a plus, however, to maintain a 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 treatment.
Varieties of lasers
The main classification implies the division of such lasers according to the type of gas mixture. We have already mentioned the features of models based on a carbon dioxide active body, but alsoionic, helium-neon and chemical media are common. To manufacture the design of the device, ion gas lasers require the use of materials with high thermal conductivity. In particular, ceramic-metal elements and parts based on beryllium ceramics are used. Helium-neon media can operate at different wavelengths in infrared radiation and in the visible light spectrum. The resonator mirrors of such devices are distinguished by the presence of multilayer dielectric coatings.
Chemical lasers represent a separate category of gas tubes. They also involve 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, the gas is used for chemical excitation. Devices of this type are advantageous in that they can directly convert chemical energy into electromagnetic radiation.
Use of gas lasers
Practically all lasers of this type are highly reliable, durable and affordable. These factors have led to their widespread use in various industries. For example, helium-neon devices have found application in leveling and adjustment operations that are performed in mine operations, 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. Was no exception in terms of practical benefits andargon gas laser, the application of which shows efficiency in the field of material processing. 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 advantageous operational properties, many users note the high directivity and overall quality of the light beam. Such characteristics can be explained by a small proportion of optical distortions, regardless of the ambient temperature conditions. As for the disadvantages, a large voltage is needed to unlock the potential of gaseous media. In addition, a helium-neon gas laser and devices based on carbon dioxide mixtures require a considerable amount of electrical power to be connected. 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 use in laser systems are still insufficiently mastered. Nevertheless, the demand for such equipment has been successfully growing for a long time, forming a corresponding niche in the market. The gas laser has received the greatest distribution in the industry. It is used as a tool for point and accurate cutting of solid materials. But there are also factors hindering the spread of such equipment. Firstly, this is a rapid wear of the element base, which reduces the durability of devices. Secondly, there are high requirements for providing an electric discharge,needed to form the beam.
