Abstract: A gas laser emits an output laser beam from a low pressure region to a region having a higher pressure. This is done through an opening in the side of a laser device. Under normal circumstances, the provision of such an opening would incur a flow of air from the high pressure side, externally of the laser device, to the low pressure side within the device. To prevent this, an aerodynamic window is placed in a passageway leading from said opening in the laser device through which the laser beam passes. A gas flow is passed across said passageway which will provide a flow which represents the flow of a segment of a free-vortex flow field having a pressure differential across the segment which is equal to that between the low and high pressure regions. A single nozzle, specifically contoured to produce a segment of a free-vortex flow field directs the gas into the passageway and an opening collects the flow onto the other side of said passageway. A method of constructing such a nozzle is set forth.

Abstract: A gas laser emits an output laser beam from a low pressure region to a region having a higher pressure. This is done through an opening in the side of a laser device. Under normal circumstances, the provision of such an opening would incur a flow of air from the high pressure side, externally of the laser device, to the low pressure side within the device. To prevent this, an aerodynamic window is placed in a passageway leading from said opening in the laser device through which the laser beam passes. A gas flow is passed across said passageway which will provide a flow which represents the flow of a segment of a free-vortex flow field having a pressure differential across the segment which is equal to that between the low and high pressure regions. A single nozzle, specifically contoured to produce a segment of a free-vortex flow field directs the gas into the passageway and an opening collects the flow onto the other side of said passageway. A method of constructing such a nozzle is set forth.