Abstract: A porous-wall compact diffuser designed for chemical laser applications. The laminar boundary layer in the diffuser is removed through the porous wall by suction provided by a chemical pump concept, thereby stabilizing the normal shock wave in the supersonic flow channel at the juncture with the wide-angle subsonic diffuser section.

Abstract: A primary nozzle provides a two-dimensionally expanding source flow of an oxidizer; a line serving as origin; and curved secondary nozzles are positioned in the primary, supersonic flow, for discharging fuel in radial direction, parallel to the oxidizer flow, mixing therewith in the laser cavity. The secondary nozzles have concavely curved, leading edges as well as concavely curved expansion edges downstream from the leading edges, positioned to cancel shockwaves from the leading edges of the respective adjacent secondary nozzles. The secondary nozzle structure provides a radially expanding fuel flow and maintains the radially expanding primary flows shock free. This radially expanding, primary flow accommodates the unused heat of reaction so that pressure is maintained nearly constant in the laser cavity. Supersonic expansion provides a low, initial pressure, and the radially expanding flow thereby maintains this pressure low.

Abstract: An optical path length changing arrangement employing a selected cross-section of pressurized gases or other fluid and usable in a space weapon chemical laser and in other optical equipment for phase changes along a transmitted wavefront. Use of a heavy, high-refraction index gas such as Freon.RTM. or nitrogen as the optical path length correcting medium is disclosed, along with adjacent buffering streams of a light, low optical refraction gas such as helium.