Abstract: A plurality of light concentrators (12) each provide light over an optical fiber cable (23) to a single optical detector (25) in a non-imaging laser radar. Each light detector may comprise a single mirror (29) or a primary mirror (20) and secondary mirror (22). A transmitter (13) within the array may comprise the same configuration as the light concentrators (12) to deliver laser light from fiber optic cables (23, 30) or may comprise a primary mirror (35) with a large hole (38) that delivers laser light to a secondary mirror (37). The array provides a very rugged large aperture which is very short, and which can be increased without any increase in length.

Abstract: A laser ranging and detection system includes a laser for generating a coherent outgoing beam and a telescope. The telescope includes a primary mirror with an aperture for receiving the coherent outgoing beam and for passing an incoming, incoherent, backscattered light. A focal system is positioned between the laser and the telescope and focusses the coherent outgoing beam so as to create a reduced beam-waist cross section at a focal plane. A beam separator is positioned at the focal plane and in a first path between the focal system and the telescope. The beam separator includes a reflective surface arranged to reflect the incoherent backscattered light to a second path for detection. The beam separator further has an optical aperture positioned in the first path, that exhibits a cross sectional area approximately equal to the reduced beam-waist cross section.

Abstract: This invention converts the fixed wavelength of a laser beam into a multiplicity of spectral output beams. The conversion process is achieved by means of an arrangement of nonlinear optical crystals in which parametric interaction generates a pair of tunable output beams in each crystal. The arrangement utilizes two stages of sequential (cascaded) parametric conversion which produces output radiation in the 2 to 5 micrometer spectral region from a laser with an output wavelength of 1 micrometer.

Abstract: A flow field seeded with small particles is illuminated by collimated, monochromatic laser light sheet 16. Doppler shifted scattering from particle motion is imaged by an optical system 22. An optical frequency-to-intensity converter 24 is located at the image plane such that the transmitted image contains a simultaneous two-dimensional measurement of flow velocity along a direction determined by a laser beam and observer (converter) direction. These images can be observed directly or through a TV-2-D array camera and monitor or processed through a computer system 28.

Abstract: A device utilizing lasers wherein efficient wavelength shifting of the generated laser radiation is provided using stimulated Raman scattering both in atomic vapor and molecular media. A coupled pair of confocal unstable resonators in conjuction with an integral injection laser is utilized in a novel optical arrangement for providing the efficient conversion of laser power into Stokes radiation without beam obscurations. The wavelength, spectral bandwidth, polarization and beam divergence are controlled by the spatial evolution of the main laser output which is locked to the seed radiation provided along the optical axis by the injection laser. Mode matching of the wavefront is automatically achieved by the use of common optical surfaces which couple the injection laser, main laser and the Raman converter. The resulting Stokes output through a partially reflecting/transmitting mirror is an unobscured beam whose intensity profile is determined by the laser medium power distribution.

Abstract: A Raman oscillator and amplifier utilizing a single Raman cell. The oscillator and amplifier portions of the cell are located either coaxially or adjacent to each other within a single Raman cell so as to provide a more compact arrangement. In Raman oscillator/amplifier systems employing high-temperature ovens, the invention also reduces heating requirements.

Abstract: A laser having its lasing medium located within two or more portions of a single optical cavity. The lasing media within different portions of a single optical cavity are excited in sequence to obtain lasing actin over an extended temporal period.

Abstract: A laser system for producing a laser beam in an unstable resonator whose spatial and temporal characteristics conform with those of a laser beam from a stable resonator. The laser system includes three reflectors, an optical switch and a laser gain medium positioned within an optical propagation path extending between the optical switch and the third reflector. The optical switch selectably exposes either the first or the second reflector to the aforesaid propagation path, the first and second reflectors being designed to form, in combination with the third reflector, a stable and an unstable resonator, respectively. In operation, the optical switch initially is set so as to include the first reflector in the laser resonator, thereby forming a stable resonator which produces a beam of laser light. A short time thereafter, the optical switch changes states so as to substitute the second reflector for the first, thereby forming an unstable resonator.