Novel aerodynamic window with a pump cavity and a supersonicjet

In order to minimize the mass flow rate and the optical distortion of aerodynamic windows, a novel type with a pump cavity and a supersonic gas jet has been developed. Prototypes of this window with an aperture of 4 x 4 qmm have been designed and fabricated. With it, a 80 mbar laser cavity can be sealed up using a gas jet of 5 g/s mass rate at 5.4 bar while the pressure in pump cavity is about 600 mbar and the volume to be pumped is less than 7.2 cbm/h. It can be operated stably if the pressure variation is less than 25 mbar. A wide range of operation pressure of the laser cavity can be realized easily by adjusting the supply pressure for the gas jet and the pressure in the pump cavity.