Gas laser apparatus, method and turbine compressor therefor

Abstract

A fast axial flow gas laser apparatus comprising an at least essentially closed loop defining a flow path for a laser gas, an arrangement for exciting gas flowing in the loop of the apparatus to cause the gas to lase, and a regenerative compressor for flowing gas through the closed loop along the flow path. The compressor is capable of operating with a pressure ratio sufficient to flow the gas along at least a portion of the loop at a speed at least half the speed of sound in the gas with inlet pressures of only a small fraction of an atmosphere. The uniform discharge pressure of the compressor results in a uniform laser discharge or output. A positive pressure fluid pressure seal prevents lubricant at a bearing support for the impeller shaft of the compressor from moving to the impeller and possibly contaminating the laser gas being compressed thereby and also prevents surrounding air from contaminating the laser gas. The pressurized fluid of the seal is permitted to migrate into the laser gas as make-up gas. The compressor is capable of moving gas through the laser at speeds approaching the speed of sound for high power output from the laser without power fluctuations and with minimal service requirements and long life while occupying only a small area within an existing laser cabinet.