| 摘要 |
PURPOSE:To keep a gas temperature constant by using a heat exchanger and to remove impurities such as dust particles or the like in a laser medium gas by installing a filter by a method wherein the laser medium gas is circulated forcibly in a laser tube in order to suppress a rise in the gas temperature in a crossing part, of laser beams, where the Raman transform is executed. CONSTITUTION:When a laser beam is incident on the inside of a laser tube 11 through an input tube 14, it is reflected several hundred times by reflectors 12, 13 and is taken out to the outside from an output tube 15. In this case, when the laser beam is reflected by the reflectors 12, 13, an angle of the input tube 14, a shape of the reflectors 12, 13 and an angle of the output tube 15 are decided in such a way that laser beams are crossed mutually in the central part of the laser tube 11. Since dust particles are trapped by using a filter 20, it is possible to prevent the dust particles whirled from a structure by a flow of a laser medium gas from flowing into the laser tube 11. Even when a light path is very long, it is possible to prevent an efficiency of the laser beam from being lowered when the laser beam is absorbed by the dust particles. In addition, the laser medium gas in a part where the laser beams are crossed and the Raman transform is executed is always replaced; accordingly, it is possible to prevent a temperature rise by using a heat exchanger 19; this apparatus can resist the continuous Raman transform. |
