Abstract: A laser diode distance measurement device includes a laser diode 10 which emits light 20 to a lens 22 which provides focussed light 24 incident on a target 26. The light 24 is reflected from the target 26 back to the laser diode 10 which causes the laser diode 10 to emit a light 28 which exhibits intensity pulses (due to coherent interference) related to the distance L to the target 26. A photodetector 30 provides a feedback signal indicative of the intensity of the light 28 to a distance measurement circuit 18. The laser diode 10 is driven by an up-ramp signal that reduces electronic processing and at a frequency that reduces speckle noise. The distance measurement circuit 18 blanks-out a portion of the feedback signal during discontinuities of the laser diode drive signal to minimize associated noise from distorting the distance measurement.

Abstract: A laser diode distance measurement device includes a laser diode assembly 10, comprising a laser diode and photodiode, which emits light 17 to a lens 19 which provides collimated light 20 incident on a float 22 which is covered with reflective tape on its top surface 24. The light 20 is reflected from the float 22 back to the laser diode assembly 10 which causes the assembly 10 to provide a signal having magnitude pulses (due to coherent interference) on a line 15 to a liquid level measurement circuit 14 related to the distance L to the float 22. Use of the collimated beam 20 and reflective tape on the float 22 minimizes speckle while providing adequate optical intensity feedback. The laser assembly 10 is driven by a sawtooth waveform signal that reduces electronic processing. The distance measurement circuit 14 blanks-out the feedback signal during discontinuities of the laser diode drive signal to minimize associated noise from distorting the distance measurement.

Abstract: A detector for laser radiation that detects the presence of above-threshold radiation in one of a set of wavelength ranges employs a set of Fresnel lenses designed to focus radiation in a particular band onto a metal-coated film. A series of Fresnel lenses is designed with constant focal lengths, but each lens is designed to have that focal length at a specific wavelength. Only when the wavelength of the incident radiation matches the design wavelength of the Fresnel lens will the film be marked or machined. Radiation of differing wavelengths will be defocused to a degree that will reduce the intensity below the level that will mark or machine the film. An electronic based version of this spectroscopy detector can also be implemented.

Abstract: A broadband optical limiter for use in combination with a sensor system is operative to prevent irradiation of the sensor system by laser radiation of unknown wavelengths having intensity levels sufficient to damage or disable the sensor system. The broadband optical limiter is further operative to throughput, with minimal optical distortion at wide angle fields of view, electromagnetic radiation in the operating spectral band(s) of the sensor system. The broadband optical limiter includes a flat or spherically shaped sacrificial mirror that is operative to reflect electromagnetic radiation in the operating spectral band(s) of the sensor system and to be optically machined, i.e., vaporized, by focused laser radiation of unknown wavelengths having intensity levels sufficient to damage or disable the sensor system to create a reflective dead spot. The reflective dead spot prevents the focused laser radiation from being throughputted to the sensor system.

Abstract: A combustion driven laser employs HBr as one of a plurality of lasing species. One embodiment of the invention lases simultaneously on the three species HF, HCl, HBr.

Abstract: A linear capillary orifice injector for producing a chemical reaction in a combustion chamber is disclosed. The orifices are judiciously arranged to form a discrete pattern for achieving a high degree of shear mixing while attaining a uniform temperature and species profile particularly necessary for chemical lasers.

Abstract: The matrix nozzle for mixing lasers in which an inner tube forms a path for he primary flow and a chamber around the inner tube opens around the outer periphery of the inner tube to form a flow path for the secondary gas flow. The exiting of the primary and secondary gases rapidly mix and cause lasing to take place. With this arrangement, the primary gas flow adds turbulence to the secondary gas flow as it exits and causes better mixing of the gases.

Abstract: A chain reaction laser system which operates with two species lasing simultaneously is disclosed. The laser is combustion-driven and provides an output of continuous wave radiation. A fluorine interhalogen and atomic fluorine are mixed together with hydrogen to induce chemical reactions which provide two species of hydrogen halides which are vibrationally excited as well as atomic hydrogen and atomic fluorine. The latter, atomic fluorine, is then available to react with additional hydrogen in a chain reaction sequence. The various preferred reactants and two preferred structures are discussed. In a first embodiment the fluorine interhalogen and atomic fluorine which are both essential to the operation of the invention are both formed as they are needed in a reaction region at relatively high temperature and pressure. In a second embodiment one reactant is formed under conditions of relatively high temperature and pressure and the other at low temperature and pressure conditions.